Which education would the nurse provide parents about the side effects of the Hib vaccine

Cochrane Database Syst Rev. 2018; 2018(5): CD010038.

Monitoring Editor: Jessica Kaufman,

La Trobe University, Centre for Health Communication and Participation, School of Psychology and Public Health, BundooraVICAustralia, 3086

La Trobe University, College of Science, Health and Engineering, BundooraVICAustralia, 3086

The University of Sydney, Sydney Nursing School, SydneyNSWAustralia, 2050

La Trobe University, Department of Public Health, School of Psychology and Public Health, BundooraVICAustralia, 3086

Abstract

Background

Early childhood vaccination is an essential global public health practice that saves two to three million lives each year, but many children do not receive all the recommended vaccines. To achieve and maintain appropriate coverage rates, vaccination programmes rely on people having sufficient awareness and acceptance of vaccines.

Face‐to‐face information or educational interventions are widely used to help parents understand why vaccines are important; explain where, how and when to access services; and address hesitancy and concerns about vaccine safety or efficacy. Such interventions are interactive, and can be adapted to target particular populations or identified barriers.

This is an update of a review originally published in 2013.

Objectives

To assess the effects of face‐to‐face interventions for informing or educating parents about early childhood vaccination on vaccination status and parental knowledge, attitudes and intention to vaccinate.

Search methods

We searched the CENTRAL, MEDLINE, Embase, five other databases, and two trial registries (July and August 2017). We screened reference lists of relevant articles, and contacted authors of included studies and experts in the field. We had no language or date restrictions.

Selection criteria

We included randomised controlled trials (RCTs) and cluster‐RCTs evaluating the effects of face‐to‐face interventions delivered to parents or expectant parents to inform or educate them about early childhood vaccination, compared with control or with another face‐to‐face intervention. The World Health Organization recommends that children receive all early childhood vaccines, with the exception of human papillomavirus vaccine (HPV), which is delivered to adolescents.

Data collection and analysis

We used standard methodological procedures expected by Cochrane. Two authors independently reviewed all search results, extracted data and assessed the risk of bias of included studies.

Main results

In this update, we found four new studies, for a total of ten studies. We included seven RCTs and three cluster‐RCTs involving a total of 4527 participants, although we were unable to pool the data from one cluster‐RCT. Three of the ten studies were conducted in low‐ or middle‐ income countries.

All included studies compared face‐to‐face interventions with control. Most studies evaluated the effectiveness of a single intervention session delivered to individual parents. The interventions were an even mix of short (ten minutes or less) and longer sessions (15 minutes to several hours).

Overall, elements of the study designs put them at moderate to high risk of bias. All studies but one were at low risk of bias for sequence generation (i.e. used a random number sequence). For allocation concealment (i.e. the person randomising participants was unaware of the study group to which participant would be allocated), three were at high risk and one was judged at unclear risk of bias. Due to the educational nature of the intervention, blinding of participants and personnel was not possible in any studies. The risk of bias due to blinding of outcome assessors was judged as low for four studies. Most studies were at unclear risk of bias for incomplete outcome data and selective reporting. Other potential sources of bias included failure to account for clustering in a cluster‐RCT and significant unexplained baseline differences between groups. One cluster‐RCT was at high risk for selective recruitment of participants.

We judged the certainty of the evidence to be low for the outcomes of children's vaccination status, parents' attitudes or beliefs, intention to vaccinate, adverse effects (e.g. anxiety), and immunisation cost, and moderate for parents' knowledge or understanding. All studies had limitations in design. We downgraded the certainty of the evidence where we judged that studies had problems with randomisation or allocation concealment, or when outcomes were self‐reported by participants who knew whether they'd received the intervention or not. We also downgraded the certainty for inconsistency (vaccination status), imprecision (intention to vaccinate and adverse effects), and indirectness (attitudes or beliefs, and cost).

Low‐certainty evidence from seven studies (3004 participants) suggested that face‐to‐face interventions to inform or educate parents may improve vaccination status (risk ratio (RR) 1.20, 95% confidence interval (CI) 1.04 to 1.37). Moderate‐certainty evidence from four studies (657 participants) found that face‐to‐face interventions probably slightly improved parent knowledge (standardised mean difference (SMD) 0.19, 95% CI 0.00 to 0.38), and low‐certainty evidence from two studies (179 participants) suggested they may slightly improve intention to vaccinate (SMD 0.55, 95% CI 0.24 to 0.85). Low‐certainty evidence found the interventions may lead to little or no change in parent attitudes or beliefs about vaccination (SMD 0.03, 95% CI ‐0.20 to 0.27; three studies, 292 participants), or in parents’ anxiety (mean difference (MD) ‐1.93, 95% CI ‐7.27 to 3.41; one study, 90 participants). Only one study (365 participants) measured the intervention cost of a case management strategy, reporting that the estimated additional cost per fully immunised child for the intervention was approximately eight times higher than usual care (low‐certainty evidence). No included studies reported outcomes associated with parents’ experience of the intervention (e.g. satisfaction).

Authors' conclusions

There is low‐ to moderate‐certainty evidence suggesting that face‐to‐face information or education may improve or slightly improve children's vaccination status, parents' knowledge, and parents' intention to vaccinate.

Face‐to‐face interventions may be more effective in populations where lack of awareness or understanding of vaccination is identified as a barrier (e.g. where people are unaware of new or optional vaccines). The effect of the intervention in a population where concerns about vaccines or vaccine hesitancy is the primary barrier is less clear. Reliable and validated scales for measuring more complex outcomes, such as attitudes or beliefs, are necessary in order to improve comparisons of the effects across studies.

Plain language summary

Face‐to‐face interventions to inform or educate parents about early childhood vaccination

Review question

The aim of this Cochrane Review was to find out whether face‐to‐face information or education delivered to parents or expectant parents improved vaccination status, parental knowledge or understanding of vaccination, attitudes or beliefs about vaccination, or intention to vaccinate. We also looked for evidence about any negative impacts of the intervention, such as anxiety, and evidence about cost and parents’ experiences of the intervention.

This is an update of a review originally published in 2013. In this update, we found four new studies, for a total of ten studies.

Background

Childhood vaccination is an important and effective way to reduce childhood illness and death. However, many children do not receive the recommended vaccines, because their parents or caregivers do not know why vaccination is important, do not understand how, where, or when to get their children vaccinated, or have concerns or doubts about vaccine safety and efficacy.

One way to inform or educate parents about vaccination is through face‐to‐face discussions, either one‐on‐one, or in groups. This strategy can be used and adapted in any setting.

Study characteristics

We included trials published up to July 2017. We found ten studies with a total of 4527 participants that looked at the effects of face‐to‐face information or education for parents. Seven studies were from high‐income countries, and three were from low‐ or middle‐income countries. The interventions were a mix of short (under ten minutes) and longer sessions (15 minutes to several hours) that were delivered to new or expectant parents.

Key results

We analysed data on the effects of face‐to‐face information or education on seven different outcomes. According to the included studies, face‐to‐face information or education may have improved children’s vaccination status, probably slightly improved parents’ knowledge or understanding of vaccination, and may slightly have improved parents’ intention to vaccinate. These interventions may have led to little or no difference in parental attitudes or anxiety related to the intervention. Only one study measured the cost of a face‐to‐face case management strategy. In this study, the cost of fully immunising one additional child was eight times the cost of usual care, but the intervention was complex, and the study was older, and not widely generalisable. No studies measured parents’ satisfaction with the face‐to‐face intervention.

Certainty of the evidence

We judged the certainty of the evidence to be moderate for parents' knowledge or understanding, but low for all other outcomes. We downgraded the certainty of the evidence where studies were judged to have problems with bias from different sources (e.g. the way in which participants were assigned to study groups), where there was a lot of variability in results or imprecise estimates, or where we had misgivings about the choice of outcomes measures.

Conclusions

This review suggests that immunisation‐focused educational messages may be sufficient to improve vaccination coverage and, to a small degree, knowledge, particularly where awareness is identified as a barrier to vaccination.

Summary of findings

Background

This review originated as a part of the Communicate to Vaccinate (COMMVAC) project (2010‐2016), which sought to build evidence for communication interventions related to childhood vaccination (Lewin 2011). This topic was selected through an international priority setting exercise because face‐to‐face communication is widely used around the world, can be implemented in a range of settings and can be adapted or tailored for different populations. A second review topic was also selected from this exercise (information or education aimed at communities (Saeterdal 2014)).

Since 2013, when the review was originally published, there have been a number of developments in the field of vaccination communication research. Most notably, research related to vaccine hesitancy has highlighted the relevance and importance of face‐to‐face communication in countries of all income levels (Ames 2017; Henrikson 2015; Jarrett 2015; Leask 2015; Opel 2013). Therefore, in recognition of the progress of the field and the potentially wider audience for this review, we have revised the Background to strengthen the explanation of the intervention's theoretical underpinnings and situate this review within the landscape of evidence published since 2013. Some information from the original review, such as the detailed definition of the terms 'inform' and 'educate', is now presented in the supporting Appendices (Appendix 1).

Description of the condition

Early childhood vaccination is an essential public health practice, carried out in every country in the world and saving two to three million lives every year (WHO 2016). In addition to reducing preventable premature mortality, the practice of vaccination is cost‐effective, increasing parent or carer productivity, and lowering health care costs by reducing childhood morbidity (Ozawa 2012; WHO 2018). Childhood vaccination also has a broader social benefit of promoting health equity by ensuring the distribution of health within populations, and contributes to the public good by supporting disease containment (Luyten 2016).

Nevertheless, over 19 million children per year do not receive all the recommended basic vaccines (WHO 2018), and coverage levels fluctuate in individual countries or populations, and for specific vaccines (Nandy 2016; Smith 2008; UNICEF 2014). While the burden of vaccine‐preventable disease is greatest in low‐ and middle‐income countries (LMICs; Oyo‐Ita 2016; Sutter 2006), outbreaks occur all over the world, including in countries with relatively high coverage (e.g. Belgium, Italy, Ireland, Australia, USA; Barrett 2016; Filia 2017; Grammens 2017; Townsville‐Mackay 2013; Zipprich 2015). Therefore, improving and maintaining global childhood vaccination rates is an ongoing public health goal, prioritised by major international health strategies and agreements, such as the UN Millennium Development Goals (UN Millennium Project 2006), the WHO‐UNICEF Global Immunization Vision and Strategy (WHO 2009), and the Global Vaccine Action Plan 2011 to 2020 (WHO 2012).

The major factors influencing vaccination coverage relate to 1) availability of the vaccine, 2) awareness of recommendations, 3) accessibility of the services, 4) acceptance of the vaccines, and 5) activation to trigger the action of getting a vaccine (Thomson 2016). Face‐to‐face interventions to inform or educate parents specifically target two of these factors: awareness and acceptance.

Enhancing awareness of vaccination and its importance is critical to address barriers associated with limited or incorrect understanding of the value of vaccines, the risks of vaccine‐preventable diseases, or the vaccine schedule itself, which evolves and changes over time (Esposito 2014). People are unable to seek on‐time vaccination if they do not know where to go, how to access services, when or which vaccines are due, or why they are important.

Vaccine acceptance and the issue of vaccine hesitancy have become a major global focus in recent years (WHO SAGE Working Group on Vaccine Hesitancy 2014a). On the continuum from complete vaccine acceptance to total refusal, hesitant individuals are more likely to refuse or delay some or all vaccines (Dubé 2016). People may feel hesitant because they don't believe vaccines are necessary ‐ a conundrum created by vaccination is that as its uptake becomes more widespread, the diseases it prevents become less visible, and people can feel less urgency to vaccinate (Smith 2015). Vaccine hesitancy is also influenced by concerns about the safety of vaccines, highlighting the critical importance of appropriate responses to safety‐related events or rumours (WHO SAGE Working Group on Vaccine Hesitancy 2014). Although more commonly discussed and researched in high‐income countries (HICs), vaccine hesitancy is a worldwide phenomenon (Dubé 2014), with notable anti‐vaccine campaigns and safety scares taking hold in the UK (Brown 2012), Pakistan (Murakami 2014), and Nigeria (Kaufmann 2009). Ensuring that parents can access, understand, and judge the quality of information sources is critical, as misinformation and rumours can take root and spread particularly rapidly in a population with a high degree of hesitancy towards vaccines (Salmon 2015).

Successful vaccination programmes rely on people having appropriate information, and sufficient knowledge, awareness, and acceptance of vaccination to make the decision to participate (Dubé 2016; Shahrabani 2009; Thomson 2016; Zyngier 2011). Interventions to inform or educate may not necessarily be sufficient to change behaviour in all cases, but this does not negate their importance (Dubé 2015; Leask 2011). Ensuring that people are informed and knowledgeable about their health is a UN‐codified human right and a principal tenet of patient‐centred care (Dwamena 2012; Hill 2011; Rodriguez‐Osorio 2008; United Nations 2008; WHO 2007). Information is fundamental to valid consent, and extensive qualitative evidence indicates that parents want more or different information about vaccines (Ames 2017).

Description of the intervention

Information and education can be provided in various ways, but this review focuses specifically on face‐to‐face communication interventions (Kaufman 2017b). Face‐to‐face communication can be interactive, adaptable, and efficient, and already accompanies the delivery of nearly every vaccine injection or drop around the world. It allows for real‐time dialogue, during which parents are able to explain their concerns or preferences and ask personally‐relevant questions. It can take place in one‐on‐one interactions, or with small groups of people. Face‐to‐face communication is particularly useful when people are semi‐literate, or not literate in either their language or the majority language of their country.

Face‐to‐face information or education can be delivered by a range of individuals (e.g. volunteers, advocates, peers), but it is particularly relevant in the context of the healthcare encounter. Healthcare providers (e.g. doctors, nurses, community health workers, Indigenous health workers) are the primary source of information for parents about routine childhood vaccination (Freed 2011; Jones 2012). Parents trust the recommendations of their providers over other sources of information about vaccination, and communication that is respectful and builds trust can help hesitant parents work through their concerns (Freed 2011; Jones 2012; Leask 2015). Conversely, poor provider communication experiences can cause parents to feel confused, disrespected, or mistrustful, and potentially make them less likely to return for their child's next vaccination appointment (Brown 2010; Leask 2012). Face‐to‐face delivery of vaccination information or education to parents is clearly influential, but the most effective messages and communication styles are not yet established. Some evidence supports a participatory communication approach for increasing vaccine acceptance (Opel 2015), while other research suggests a more presumptive communication style may be more effective at increasing uptake (Brewer 2017).

In addition to one‐on‐one discussions with providers, face‐to‐face interventions to inform or educate may include oral presentations, individual or group classes or seminars, information sessions, or home outreach visits. Such interventions may be undertaken on their own, or combined with other interventions (e.g. telephone contact). This review focused on face‐to‐face communication with parents or guardians of preschool‐aged children, either individually or in groups. Interventions directed to adolescents were not included, as our focus was on early childhood vaccines. Interventions directed to communities are addressed by a separate review (Saeterdal 2014). Interventions directed to healthcare providers, such as professional education or communication training interventions, were also outside the scope of this review.

After a thorough investigation of the definitions of the words 'information' and 'education' (see Appendix 2), we determined that there was no reliable way to distinguish between the two across studies. A recent comprehensive table of definitions of education‐ and training‐related terms developed by the World Federation of Public Health Associations working group on Public Health Education and Training supports the conclusion that 'education' and 'information' are largely considered coterminous (WFPHA 2017). Therefore, we included any trial evaluating an intervention that aimed to inform, educate, or both, in this review.

How the intervention might work

While creating a generally informed and health literate populace is an important public health goal, most information or educational interventions aim to change or support specific health behaviours. The interventions in this review targeted the parental health behaviour of vaccinating their young children on time, and with all recommended vaccines.

Behaviour change is complex, and a number of theories outline potential factors and antecedents that may predict or influence an individual's behaviour (see Appendix 2 for an overview of several relevant theories). The Health Belief Model (HBM) is a key behaviour change theory that is particularly relevant for vaccination, as it was developed to explain people's participation in preventive health programmes, including vaccination (Champion 2008; Janz 1984). According to the HBM, the decision to take action ‐ or not ‐ is a product of a number of variables: perceived severity (of vaccine‐preventable diseases (VPDs)); perceived susceptibility (of one's child to VPDs); perceived benefits (of vaccination); perceived barriers (to getting vaccinated); and self‐efficacy (perceived ability to act). Each of these variables may be influenced by an information or educational intervention.

Several other health behaviour change theories (e.g. the Theory of Reasoned Action (TRA), Theory of Planned Behaviour (TPB), Integrated Behavior Model (IBM) share the idea that the most important determinant of behavioural action is behavioural intention (Ajzen 1985; Ajzen 1991; Montaño 2008). These theories suggest that intention is based on a combination of attitudes (i.e. how a person feels about the behaviour), subjective norms (i.e. social pressure related to the behaviour), and perceived behavioural control (i.e. whether the person feels able to act). The IBM also explicitly recognises the importance of a person having sufficient knowledge and skills to perform the behaviour. Again, information or educational interventions can potentially impact vaccination behaviours by targeting any of the contributing factors identified in these models. For instance, learning about vaccine safety and efficacy may foster positive attitudes towards vaccines. Interventions could increase parents' perceived behavioural control by helping them to understand how, where, and when to vaccinate their children.

Interventions that intend to inform or educate do not necessarily mean just passively giving people information. While this may be adequate when the primary barrier to vaccination uptake is a lack of knowledge or a lack of access to necessary information, there is considerable evidence to suggest that interventions that just provide information are not necessarily sufficient to change behaviour (Goldstein 2015; Ryan 2014). In some cases, this may be because external barriers still exist, such as barriers to availability of the vaccine and access to the service. In other cases, people may not actually receive the intended information, they may not be able to understand it, they may not trust it, or it may be inaccurate. For certain individuals with firmly‐rooted opposing beliefs, receiving factual information may actually backfire, and further entrench their opposing views (Nyhan 2014; Nyhan 2015). Therefore, it is important to recognise that information or educational interventions can involve much more than information provision ‐ they can be interactive, tailored, and targeted. Increasingly, interventions are designed with a theoretical underpinning, and are supported by qualitative data (Corace 2016; Jones 2014; Leask 2012). An appropriately designed information or educational intervention can potentially influence not only parents' knowledge, but also their attitudes, perceptions about their peers, sense of self‐efficacy, intention to vaccinate, and ultimately, their vaccination behaviours.

Why it is important to do this review

Interventions whose manifest purpose is to inform or educate people about vaccination are extremely common, reflecting a focus on information‐giving and the provider‐parent communication encounter as potential strategies to influence vaccination decision making. Despite this, few trials and no systematic reviews of randomised controlled trials (RCT) have evaluated the effects of face‐to‐face communication, and most research is qualitative or observational. In addition, many trials in the vaccination communication area do not measure key intermediate outcomes that help decision‐makers understand whether, and how, an intervention works (Kaufman 2016). Therefore, there is an urgent need to establish a rigorous evidence base that considers the full range of relevant outcomes to guide implementation decisions and practice guidelines (Leask 2014).

This review's comprehensive, global approach includes face‐to‐face communication that aims to address both awareness and acceptance of vaccination. While much of the research about vaccine hesitancy and provider‐parent communication focuses exclusively on HIC settings, face‐to‐face communication is a globally‐relevant strategy that is widely used in LMICs as well as HICs. This topic was identified as important by vaccination programme managers, policymakers, researchers and other stakeholders from LMICs in deliberative forums that informed the original review (Lewin 2011). It is critical to determine the effects of face‐to‐face interventions ‐ including their content, format and timing ‐ so that valuable resources can be allocated appropriately.

Relationship to other reviews

Since this review's original publication in 2013, there have been a number of new or updated systematic reviews published on related topics. In Table 2, we briefly summarised several relevant non‐Cochrane reviews. These reviews generally differ from ours in that they included a broader range of intervention types or study designs; they did not incorporate risk of bias assessment in the presentation of their results; they included vaccinations for adolescents or adults as well as children; or they focused exclusively on LMICs. While there was some variation in the conclusions drawn by the authors of these reviews, most agreed that there was a shortage of high‐quality RCT evidence on the effects of information or educational interventions for childhood vaccination.

1

Summary of related non‐Cochrane reviews

In addition to the relevant non‐Cochrane reviews outlined in Table 2, this review is also closely related to three Cochrane reviews (Ames 2017; Oyo‐Ita 2016; Saeterdal 2014). Authors of each of these reviews include members of the COMMVAC project team.

The Oyo‐Ita 2016 review considered all interventions evaluated in LMICs to improve vaccination coverage. This included interventions such as incentives, education, supportive supervision, or outreach directed at parents, caregivers, and communities. The review found fourteen studies conducted in LMICs, thirteen of which were assessed to be at high risk of bias. The majority involved a communication element (e.g. health education, home visits, information campaigns). There was generally low‐ to moderate‐certainty evidence that health education and information campaigns improved vaccination coverage in LMIC settings. Our review is global in scope and focuses on face‐to‐face communication only, while the Oyo‐Ita review included all intervention types, but focused on studies conducted only in LMICs. Three studies appeared in both reviews, but these studies were contextualised in different ways, based on the scope of the respective reviews (Bolam 1998; Usman 2009; Usman 2011).

Saeterdal 2014 included vaccination communication interventions aimed at communities, which we did not include in this review. The authors defined 'community‐aimed' interventions as 1) interventions directed at a geographic area, 2) interventions directed to groups of people who shared at least one common social or cultural characteristic, or both. Our review focused on interventions directed to parents, individually or in groups, whereas Saeterdal 2014 included interventions directed to groups, which may or may not have included parents. The authors found low‐certainty evidence from two cluster‐RCTs that interventions aimed at communities may improve attitudes towards vaccination, and probably increased vaccination uptake under some circumstances, when compared with routine practices. This review is currently being updated.

The Ames 2017 review included qualitative studies exploring parents' and caregivers' views and experiences of communication about childhood vaccinations, and the influence of communication on their decision making. Ames 2017 used thematic analysis to synthesise data from 38 studies, primarily from high‐income countries. The authors had high confidence in the evidence for the following findings: parents wanted more information than they receive; parents wanted balanced information about benefits and harms of vaccination; parents viewed healthcare workers as important sources of information; and parents found it difficult to know what information sources to trust, or how to find unbiased information. The authors compared their qualitative findings with the results of the trials included in the originally published version of this review (Kaufman 2013), and in Saeterdal 2014. They determined that most of the interventions evaluated in the trials addressed at least one aspect of communication that was important to parents (e.g. tailoring information to parent needs).

Objectives

To assess the effects of face‐to‐face interventions for informing or educating parents about early childhood vaccination on vaccination status and parental knowledge, attitudes, and intention to vaccinate.

Methods

Criteria for considering studies for this review

Types of studies

Randomised controlled trials (RCTs) and cluster‐RCTs. We excluded all studies rated at a high risk of bias on the random sequence generation criteria of the 'Risk of bias' tool, because we considered these studies to be quasi‐RCTs.

Types of participants

Communication interventions about childhood vaccination are often complex because multiple participant groups are involved in the delivery and receipt of the intervention. The intervention is delivered to one group (parents) to promote vaccination, which is administered to another group (children). The planning and implementation of the intervention or the vaccination programme itself is addressed by a third group (program organisers). The three participant groups were:

• Children: infants (less than 1 year) or preschool‐aged children (1 to 5 or 6 years). We only included RCTs with school‐aged children if the main focus of the intervention was vaccines whose primary series began in infancy or preschool‐aged children.

• Parents: parents, guardians, or others fulfilling the parental role, alone or in groups, targeted to receive face‐to‐face information or education, and who had at least one child due or overdue for childhood vaccinations. We also included participants who were expectant parents, individuals or couples currently pregnant, considering adoption, or otherwise expecting to become guardians of a child. The intervention could have been directed to parents individually or in groups.

• Vaccine program organisers: anyone involved in the planning or implementation of vaccination programmes or interventions

Types of interventions

Face‐to‐face communication interventions directed to parents to inform or educate them about routine childhood vaccinations. Such interventions describe or impart information about some feature of routine childhood vaccination with the purpose of changing parent knowledge, beliefs, attitudes, behaviour, or self‐efficacy. The type of content that may be covered includes information about: vaccine‐preventable diseases (e.g. symptoms, prevalence, transmission, severity); vaccines (e.g. delivery method, dose, ingredients, schedule, risks or side effects, benefits); or vaccine service delivery (e.g. where to go to receive vaccinations, costs, clinic opening hours, services to assist with access). Despite potential heterogeneity of intervention content or intensity across studies, we agreed that interventions with the purpose of informing or educating parents about vaccination were sufficiently similar to conceptually group for analysis in this review.

We included interventions delivered by anyone, including physicians, nurses, midwives, health visitors, or other healthcare professionals; trained volunteers; lay health workers; members of the community; or peers.

The term 'routine vaccinations' means all routine childhood vaccines outlined by the WHO (WHO 2018). Human papillomavirus vaccine (HPV) was excluded, because it is delivered to adolescents. This review focused only on interventions about early childhood vaccines because interventions related to vaccines for older children may be significantly different in nature (e.g. they may target children directly, or have a reduced focus on the parent's role in decision making).

We included face‐to‐face interventions conducted in cluster‐RCTs in the context of a mass vaccination campaign if it was possible to isolate and report the effects of the face‐to‐face communication interventions delivered to parents for the vaccination of young children or infants from the larger campaign. Similarly, we included multi‐component interventions with a face‐to‐face element if the outcomes of the face‐to‐face intervention alone could be determined from the reported data. For example, trials of multi‐component interventions involving face‐to‐face education plus reminders or health service access assistance measured both vaccination status and knowledge (Quinlivan 2003; Wood 1998). We could not isolate the effect of the face‐to‐face intervention on the vaccination rate, but we could attribute any changes in knowledge to the face‐to‐face educational intervention alone. We may also have been able to determine the effect of a face‐to‐face intervention if a trial measured outcomes at multiple or staged time points (or both), including assessment of the effects of one intervention component or type before the addition of other intervention types. We did not consider Interventions to be multi‐component if a secondary form of information or education (e.g. a pamphlet) was provided along with the face‐to‐face intervention that was specifically described as supplementary or supporting.

In this updated review, we tightened our inclusion criteria with regard to complex, multi‐topic, early parenting education and information interventions (e.g. well‐child appointments or home visits). Such interventions generally cover a broad range of issues, which may be tailored to the individual participant. It is often unclear whether and what kind of vaccination information is discussed, or whether every participant receives the same information or education related to vaccination. These trials may measure vaccination uptake or status, but this may be used as a general health access indicator, and does not necessarily confirm that vaccination was a topic of discussion (or indeed a focus of the intervention). This review focused on face‐to‐face information or education that was specifically about vaccination, so our updated process for determining inclusion or exclusion of such studies was as follows:

1. If the trial specifically described the vaccination content in the intervention, and it met other inclusion criteria, we included it.

2. If the trial briefly mentioned that vaccination was a topic covered by the intervention, but did not describe the content in any detail, we included it only if it also measured a vaccination‐specific knowledge, attitude, or intention outcome (indicating that vaccination was covered to some degree within the content of the intervention).

3. We excluded trials that only mentioned vaccination briefly or not at all, and measured only vaccination status, on the grounds that the intervention was not primarily an information or educational intervention about vaccination.

We welcome contact from any authors who believe their studies may have been erroneously excluded based on our interpretation of the trial report.

This updated review addressed two comparisons:

1. Face‐to‐face interventions directed to parents versus control (usual care or passive intervention, i.e. non‐face‐to‐face information or education, or no intervention),

2. Face‐to‐face intervention A versus face‐to‐face intervention B.

We reduced the comparisons from the original review, which considered the effects of the intervention when directed to individual parents or to groups of parents. There was no clear evidence to suggest that education delivered in a group setting was likely to work differently from education delivered to individuals, and so we felt that this comparison was less informative for end users of the review.

We included face‐to‐face interventions designed to inform or educate, which may have included oral sessions, lectures, one‐on‐one or group classes or seminars, information sessions, home visits, or outreach sessions.

We did not include community‐directed interventions, as these were considered in the Saeterdal 2014 review.

Types of outcome measures

Primary outcomes

1. Children: vaccination status of child (i.e. vaccination status up‐to‐date, or receipt of one or more vaccines, as defined by study authors); outcome domain: vaccination status and behaviours

2. Parents: knowledge or understanding of vaccination; outcome domain: knowledge or understanding

3. Parents: attitudes or beliefs about vaccination; outcome domain: attitudes or beliefs

4. Parents: intention to vaccinate child; outcome domain: attitudes or beliefs

5. All categories: adverse effects; outcome domain: any

Secondary outcomes

1. Parents: parent experience of intervention (e.g. satisfaction, assessment of communication); outcome domain: communication delivery and design

2. Vaccine programme managers: cost of implementing intervention; outcome domain: cost

Justification of outcome measures

Our recent research to define and prioritise core outcome domains for the evaluation of vaccination communication interventions informed the selection of outcomes for this review (Kaufman 2017; Kaufman 2017a). First, we developed a taxonomy of potential vaccination communication outcomes that were derived from trials, non‐vaccination health communication studies, and focus groups with stakeholders (parents, healthcare providers, researchers, and policymakers; Kaufman 2017). This taxonomy organised outcomes into eight domains: 1) knowledge or understanding, 2) attitudes or beliefs, 3) vaccination status and behaviours, 4) communication delivery and design, 5) community participation, 6) decision making, 7) health status and well‐being, and 8) cost.

Using a Delphi survey, we asked representatives from each stakeholder group to rate the relative importance of each of these outcome domains when evaluating a communication intervention to inform or educate about vaccination (Kaufman 2017a). The top four domains for this type of intervention, according to stakeholders, were 'knowledge or understanding', 'attitudes or beliefs', 'vaccination status and behaviours', and 'communication delivery and design'. Therefore, we ensured that outcomes from each of these domains were captured by this review.

While changes in knowledge are not always directly linked to changes in health behaviours, we included knowledge as a primary outcome because improving knowledge was the stated purpose of many programmes and interventions (Ryan 2014). Particularly with complex communication interventions, it was important to measure intermediate outcomes that reflected the intervention's purpose, in addition to endpoint outcomes, such as vaccination status (Craig 2008; Moore 2015; Petticrew 2011; WHO SAGE Working Group on Vaccine Hesitancy 2014). Doing so could help to unpack how and whether an intervention worked or where it broke down.

In our taxonomy of outcomes, intention to vaccinate fell under the domain of 'attitudes or beliefs'. However, we decided to include two separate outcomes associated with this domain; one broadly defined as 'attitudes or beliefs', and the more specific outcome of 'intention to vaccinate'. Intention and attitudes are separate determinants of behaviour in most behaviour change theories (see How the intervention might work), with intention more directly preceding behaviour change. Changes in intention, but not behaviour, may indicate the presence of external barriers to vaccination (daCosta 2005). In comparison, changes in attitudes may be particularly relevant for identifying subtle shifts in vaccine acceptance or hesitancy that are not reflected by changes to either intentions or behaviours.

We included the outcome 'parent experience of the intervention', because the way in which communication is delivered and received can substantially impact its overall effectiveness. For instance, parents cited poor communication experiences with healthcare providers made them less likely to consider or undertake vaccination (Leask 2012; Leask 2015).

While it was not prioritised in the Delphi survey, we also included cost as an outcome in this review. The cost of implementing an intervention is particularly important to record, if it is measured, to improve equity in healthcare delivery and to increase the global applicability of research evidence. Cost is an important factor for decision and policy makers, so we included it, where reported. We included adverse events to capture any potential negative effects of the interventions ‐ for example, anxiety or distress ‐ and because it is Cochrane policy for systematic reviews to consider adverse effects (Loke 2011).

We did not include or exclude studies on the basis of whether the chosen outcomes were measured or reported.

Search methods for identification of studies

Electronic searches

We searched the following sources:

• Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 7) in the Cochrane Library (searched 3 July 2017);

• MEDLINE Ovid (2012 to July 3 2017);

• Embase Ovid (2012 to July 3 2017);

• CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 2012 to July 3 2017);

• PsycINFO Ovid (2012 to July 3 2017).

We tailored strategies to each database and reported them in the appendices section of the review (Appendices 4 to 9). We had no language or date restrictions.

In this update, we did not search two databases previously searched for the original review: Global Health (CAB) and Global Health Library (WHO). For a full list of the searches run in the original review, see Appendix 3. These databases had a very low yield of relevant RCTs, and we determined that any studies indexed in these databases would also be found via other databases and resources.

Searching other resources

• We searched all ongoing trials in ClinicalTrials.gov (searched July 2017) and the WHO International Clinical Trials Registry Platform (ICTRP) for any ongoing trials registered since 2012 (searched July 2017). We contacted authors to obtain further information or eligible data, if available.

• We searched for grey literature in OpenGrey (http://www.opengrey.eu/; searched July 2017). The Grey Literature Report, a database searched in the original review, has been discontinued, so we did not search it for this update.

• We searched the reference lists of all included papers, and any key papers in the field. We also searched the ISI Web of Science (both the Social Science Citation Index and the Science Citation Index; searched July 2017), and Google Scholar (searched August 2017) for papers that cited the studies included in the review. We contacted authors of included studies and vaccination experts and asked for additional references.

Data collection and analysis

Selection of studies

We combined all electronic database search results in Endnote and removed duplicate records. Two review authors (JK and LW) independently screened all titles and abstracts to assess which studies met the selection criteria. These authors also independently screened all ongoing trials, grey literature, and studies identified through reference list or reverse citation searching. We excluded studies that clearly did not relate to the selection criteria. We retrieved the full text of all studies determined to be potentially relevant. Two review authors (JK and LW) independently screened these studies for inclusion. They resolved disagreements through discussion with another review author (RR). We reported studies excluded at this stage in the screening process in the 'Characteristics of excluded studies' table. We provided citation details and any available information about ongoing studies, and collated and reported details of duplicate publications, so that each study (rather than each report) was the unit of interest in the review. We reported the screening and selection process in an adapted PRISMA flow chart (Stovold 2014).

Data extraction and management

Two review authors (JK and LW) independently extracted the data from included studies and discussed any disagreements with a third author (RR) until consensus was reached. We used a revised version of the data extraction form used for the original review, which combined features of the template developed by the Cochrane Consumers and Communication Review Group (CCC 2016), the Cochrane equity checklist (Ueffing 2012), and the COMMVAC extraction template. The data extraction form included the following components: details of study, participant characteristics, country and health system features, setting, intervention, intervention quality, co‐interventions, risk of bias, outcomes, and study conclusions. We reported this information for each included study in the 'Characteristics of included studies' table. One review author (JK) entered all data into Review Manager 5 (RevMan 5; RevMan 2014); a second review author (LW or RR) independently checked for accuracy against the data extraction sheets.

Assessment of risk of bias in included studies

We assessed and reported on the methodological risk of bias of included studies in accordance with the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a), and the guidelines of the Cochrane Consumers and Communication Review Group (Ryan 2013), which recommend the explicit reporting of the following individual elements for RCTs: random sequence generation, allocation sequence concealment, blinding (participants, personnel), blinding (outcome assessment), completeness of outcome data, selective outcome reporting, other sources of bias, such as contamination. We considered blinding separately for different outcomes where appropriate (e.g. blinding may affect subjective outcomes differently from objective ones), but made an overall judgment of the risk of bias for this element. For each criteria, we described the relevant information provided by the authors and judged each criteria as being at high, low, or unclear risk of bias, as set out in the judging criteria provided in Higgins 2011. We deemed studies to be at the highest risk of bias if they scored high or unclear on either sequence generation or allocation concealment (based on growing empirical evidence that these factors are particularly important in influencing risk of bias; Higgins 2011).

For cluster‐RCTs, we assessed the risk of bias associated with an additional factor: selective recruitment of cluster participants (Ryan 2013).

In all cases, two authors (JK, LW or RR) independently assessed the risk of bias of included studies, and resolved any disagreements by discussion, to reach consensus. We contacted study authors for additional information about the included studies, and for clarification of the study methods, as required. We incorporated the results of the 'Risk of bias' assessment into the text of the review, through systematic description and commentary about each of the elements, and in standard tables, leading to an overall assessment of the risk of bias of included studies, and a judgment about the internal validity of the review's results.

Measures of treatment effect

For dichotomous outcomes (e.g. vaccination status), we analysed data based on the number of events and the number of people assessed in the intervention and comparison groups. We used these to calculate the risk ratio (RR) and 95% confidence intervals (CI).

For continuous measures (e.g. knowledge or understanding, attitudes, or beliefs), we analysed data based on the mean, standard deviation (SD), and number of people assessed, for both the intervention and comparison groups, to calculate the mean difference (MD) and 95% CI. If the MD was reported without individual group data, we had intended to use this to report the study results. If more than one study measured the same outcome using different scales, we calculated the standardised mean difference (SMD) and 95% CI using the inverse variance method in RevMan 5.

Vaccination status was defined slightly differently across studies (e.g. receipt of single or multiple vaccines; 'up to date' status for complete schedule). We accepted the definition of vaccination status used by study authors. We recorded these in the 'Characteristics of included studies' tables.

Where studies used two separate methods to measure the same outcome (e.g. two measures of parental knowledge), or measured two different outcomes that could be considered part of the same outcome category (e.g. receipt of one vaccine and completion of all vaccines, which both fall under 'vaccination status'), we adopted the approach outlined by Brennan and colleagues (Brennan 2009).

1. We selected the primary outcome identified by the study authors that correlated to our stated outcomes of interest.

2. If no primary outcome was specified, we selected the one specified in the sample size calculation.

3. If there was no sample size calculation, we ranked the reported effect estimates and selected the outcome with the median effect estimate. When there was an even number of outcomes, we included the outcome whose effect estimate was ranked n/2, where n was the number of outcomes.

Several studies measured multiple aspects of parent attitudes or beliefs (e.g. perceived severity of diseases, perceived benefit of vaccines, necessity of vaccines, self‐efficacy). We compared the descriptions of these outcomes across studies, and selected the outcome from each that was most similar, in terms of what was measured and the direction of the scale used. We described all measures of attitudes or beliefs reported in each study in Table 3.

2

Additional measures of parent attitudes

Where studies recorded outcome data at multiple time points, we reported the data from the final follow‐up, because this time point may capture people who were delayed in obtaining vaccination directly following the intervention. We extracted outcome data recorded at other time points and reported these in Additional tables 8 to 12.

Unit of analysis issues

The two cluster‐RCTs used intraclass correlation coefficient (ICC) to adjust their sample sizes to account for clustering, and conducted appropriate analysis, but did not report their effective sample sizes. Therefore, we recalculated effective sample sizes based on information reported in each study, and divided the reported sample size by the design effect (Higgins 2011). In Jackson 2011, the authors used longitudinal analysis because they felt that the participant and cluster numbers were too small to use multilevel modelling. Saitoh 2017 used a hierarchical linear mixed‐effects model to account for repeated measures, by adjusting for interactions between groups, time, and groups x time (as fixed‐effect) and participants (as random‐effects).

We calculated the design effect (DE), using the ICC reported in each study (0.05) and the number of clusters in each study. For each reported outcome, we divided the original sample size by the DE to establish the effective sample size (Higgins 2011; McKenzie 2016). For the dichotomous outcome of vaccination status, we also divided the number of events occurring in each group by the DE. We reported the adjusted sample sizes in all meta‐analyses, and reduced the weightings given to these studies.

Saitoh 2017 reported a DE of 1.95, based on an average cluster size of 20. There were 100 participants in the intervention group and 88 in the control group, which we adjusted to 51 (intervention) and 45 (control) for all outcomes.

Jackson 2011 reported a DE of 1.5, based on an average cluster size of 11. There were 68 in the intervention group and 67 in the control group, which we adjusted to 45 (intervention) and 45 (control) for all outcomes.

Dealing with missing data

Where necessary, we contacted study authors for missing outcome data, missing study‐level participant characteristics, or missing summary data. We had intended to impute missing summary data where possible, and report any assumptions in the results tables. We investigated the effect of our choice of any imputed data, including ICCs, on the pooled effect estimate through sensitivity analyses.

Assessment of heterogeneity

We assessed statistical heterogeneity through visual inspection of forest plots, and the Chi² test for heterogeneity. We quantified the heterogeneity using the I² statistic; however, we did not set a threshold for acceptable heterogeneity. As Pigott and Shepperd explain, complex interventions are much more likely to appear heterogeneous, but this does not necessarily mean they are not comparable (Pigott 2013). The decision to meta‐analyse or not should ultimately be made by the reviewers. In this review, the interventions were very tightly defined, even though there could be variability in design or delivery. The target population was parents in all instances, regardless of setting. Therefore, while we anticipated some variability, we expected that the intervention would be working in largely the same way across included populations. We discuss the potential sources and implications of heterogeneity in our analysis, and assessment of the certainty of the evidence, using GRADE methodology.

Assessment of reporting biases

We assessed reporting bias qualitatively, based on the characteristics of the included studies (e.g. if only small studies were identified that indicated positive findings in favour of face‐to‐face information or educational interventions, or if information that we obtained from contacting experts in the area and the authors of retrieved studies suggested that there were unpublished studies). We did not find sufficient RCTs (at least 10) to construct a funnel plot to formally investigate small study effects or publication bias (Higgins 2011).

Data synthesis

We presented summary statistics for each of our outcomes in table form (see Table 4; Table 5; Table 6; Table 7; Table 8). These tables include data for each study group and the timing of outcome assessments.

3

Vaccination status outcome data

4

Knowledge outcome data

5

Attitudes outcome data

6

Intention to vaccinate outcome data

7

Adverse effects outcome data

The decision to conduct a meta‐analysis was based on an assessment of whether the participants, setting, interventions, and outcome measures in the included trials were similar enough to draw meaningful conclusions from a statistically pooled result. Our consideration also depended on the availability of data from two or more primary studies for pooling. Due to the variability in the populations and interventions of the primary studies, we used a random‐effects model. One included cluster‐RCT was not included in the meta‐analysis because it did not report usable data (Bjornson 1997). Where possible, we pooled relative risks and calculated associated 95% confidence intervals to measure the effects of:

1. Face‐to‐face interventions directed to parents versus control (usual care or passive intervention, i.e. non‐face‐to‐face information or education, or no intervention), or

2. Face‐to‐face intervention A versus face‐to‐face intervention B.

We described the findings in the text of the review, with consideration of the potential impact of bias on the size or direction of the effect, the degree of heterogeneity and its possible sources, and their relevance to practice. Where we were unable to conduct a meta‐analysis, we grouped the data based on the comparison and outcome domain. Within each category, we presented the data in table format, and narratively described the results, grouped by outcome.

Subgroup analysis and investigation of heterogeneity

We did not plan any subgroup analyses at the protocol or original review stages. However, in this update, we made a post hoc decision to conduct two formal subgroup analyses to investigate potential sources of statistical heterogeneity in studies reporting vaccination status. The subgroups were relevant to practice and implementation, and were related to the delivery of the intervention (length of intervention session), and the number of vaccines received. Length of intervention delivery has important time and cost implications for decision makers and providers. We considered a subgroup analysis for the number of vaccines received following advice from vaccination experts, based on the possibility that receiving one vaccine may be less demanding, as an outcome, than receiving several.

Sensitivity analysis

We did not find enough studies to undertake a sensitivity analysis based on 'Risk of bias' assessment as planned. If we had found more studies, we had planned to remove those at the greatest risk of bias from the analyses. We also had intended to conduct sensitivity analyses to check the effects of imputed data (including imputation of ICC values), and to compare fixed‐effect and random‐effects analyses, in the event that small study effects were identified by funnel plots.

Assessing the certainty of the evidence

Two authors (JK, RR) independently assessed the certainty of the evidence, using the GRADE criteria. We assessed and reported the certainty of the evidence for each outcome, assessed against concerns of risk of bias, inconsistency, imprecision, indirectness, and publication bias, based on the methods described in chapter 11 of the Cochrane Handbook for Systematic Reviews of Interventions (Schünemann 2011).

We prepared Table 1 to present the results for each of the major primary outcomes, including potential harms, as outlined in the Types of outcome measures section. We converted results into absolute effects when possible, and provided a source and rationale for each assumed risk cited in the table.

for the main comparison

Consumer participation

Those with a potential interest in this review include vaccine programme managers, policy makers, practitioners, and parent interest groups. In the peer review process for the protocol and the review, we sought external referees reflecting these interests (Kaufman 2012; Kaufman 2013). In addition, the outcomes selected in this review reflect the findings of a multi‐stage body of work that sought the views and outcome preferences of parents, healthcare providers, policy makers, and researchers (Kaufman 2017; Kaufman 2017a).

Results

Description of studies

Results of the search

In total, we identified 8247 new records through electronic database searches and 1416 records from other sources (Figure 1). After removing duplicates, we screened the title and abstract of 7177 reports, excluding 7141. We gathered 33 full‐text articles that appeared to be relevant (31 from databases and 2 from citation searches), as well as 3 records of ongoing studies (see Ongoing studies). Of these, we excluded 29 articles and records (see 'Characteristics of excluded studies' table).

Study flow diagram: 2018 review update

We excluded one previously included study, due to the decision to exclude multi‐topic, early parenting interventions from this update (Bartu 2006). We also included one previously excluded study, based on our revised assessment of the informational and educational nature of the intervention (Jackson 2011).

Included studies

We included a total of 10 trials in this update. In addition to the six trials from the original review, we added four new trials described in seven papers (see 'Characteristics of included studies' table). We identified all the new trials through database searches. We found three ongoing studies by our searches of trial registries (JPRN‐UMIN000012575; NCT02666872; NCT02984007). We contacted the authors of all included studies to clarify methods or to request additional data or intervention details. Some study authors responded with information on most, but not all queries, and one study author did not respond.

Sample size

Five studies involved between 100 and 250 participants, and five had more than 400 participants, including three studies with over 750 participants (Hu 2017; Usman 2009; Usman 2011). In two cluster trials, the effective sample sizes were calculated to be less than 100 (Jackson 2011; Saitoh 2017).

Participants and setting

The interventions were directed to mothers and parents, or expectant mothers or parents, and largely took place in clinics, hospitals, or other healthcare settings. Two studies targeted mothers for whom additional barriers to accessing vaccination exist (adolescent mothers, mothers of low socioeconomic status) (Quinlivan 2003; Wood 1998). Most studies took place in high‐income countries: Australia, Canada, China, England, Japan (two studies), and the USA, with the exception of Nepal, and Pakistan (two studies). Study features and settings are outlined in Table A.

Table A: Study features and settings

Interventions

Six studies had a single intervention arm and a single control arm (Bjornson 1997; Hu 2017; Jackson 2011; Quinlivan 2003; Saitoh 2017; Wood 1998; Table B). The face‐to‐face education in Bjornson 1997 was actually the control arm, which was compared to an educational video intervention. For the purposes of this review, that designation was reversed. Four studies had additional intervention arms. There were two intervention groups in Saitoh 2013 (Group 1: prenatal education; Group 2: postnatal education). We combined data from these into a single intervention group (receiving education either pre‐ or postnatally). There were three relevant intervention arms in Bolam 1998 (Group A: education at birth and three months after birth; Group B: education at birth only; Group C: education at three months after birth only). The outcome data we included in this review was that recorded at three months post‐natally, when Groups A and B had both received education at birth (combined into a single intervention group) and Groups C and D (control) had not. Usman 2009 and Usman 2011 measured identical interventions delivered to populations in different areas (urban and rural). Each featured one relevant intervention arm (centre‐based education only), and two arms that were not relevant to this review (re‐designed immunisation card with or without centre‐based education).

Table B: Intervention features

aThis review reports the 3‐month time point, where Groups A + B (intervention received once) were compared to Groups C + D (no intervention). At the 6‐month time point, reported in the study but not used in the meta‐analysis, Group A had received the intervention twice (birth and 3 months postpartum), Group B received it once (birth only), and Group C received it once (3 months postpartum only). Complete details for all intervention arms are available in Additional Tables.

Comparison 1: Face‐to‐face interventions directed to parents versus control

All included studies assessed face‐to‐face interventions directed to parents, but there were variations in their intensity, content, length, and control group intervention.

Seven studies evaluated a single intervention session, and three evaluated multi‐session interventions. Most interventions focused exclusively on delivering vaccination information, but interventions in three studies addressed a wider range of child health topics (e.g. breastfeeding, oral rehydration; Bolam 1998; Quinlivan 2003; Wood 1998).

There was considerable variation in the length of individual educational sessions evaluated across studies. Sessions were short (ten minutes or less) in five studies, and longer than 15 minutes in the remaining studies, including very long sessions ‐ over an hour ‐ in two studies (Jackson 2011; Quinlivan 2003).

In four studies, it appeared there was no education provided to the control group (Bolam 1998; Hu 2017; Usman 2009; Usman 2011). In one study, control group participants received routine information, but only about those vaccines required by law (Saitoh 2013). Because the intervention focused on different vaccines that were not legally required (Hib, HBV, and PCV7), we categorised the control group for this study as not receiving any education. Control groups in three studies received printed educational materials describing MMR (Jackson 2011), or general routine vaccination information (Saitoh 2017; Wood 1998). In one study, control participants received some routine vaccination information, but the format in which it was provided was not described (Quinlivan 2003). The control group in Bjornson 1997 received an educational video covering the same topics as the face‐to‐face education.

Comparison 2: Face‐to‐face intervention A versus face‐to‐face intervention B

No studies compared different types of face‐to‐face interventions.

Outcomes

Vaccination status

Please see Appendix 4 for the glossary of vaccination acronyms.

Vaccination status was measured in nine of the ten included studies. However, in two studies that assessed multi‐component interventions, the effect of the face‐to‐face intervention on changes to vaccination status could not be isolated from the effects of other components of the intervention. Therefore, we could not report on this outcome for these studies (Quinlivan 2003; Wood 1998).

Of the remaining seven studies, four measured appropriate or up‐to‐date vaccination for multiple vaccines at a particular age, and three measured receipt of a single vaccine (MMR or DPT). Outcomes were assessed in different ways. The final (or only) measurement time point for most studies was approximately three months post‐intervention, but Saitoh 2017 measured this outcome at six months and Hu 2017 at 12 months. Bolam 1998 measured vaccination status at both three and six months. We reported the three‐month time point because this allowed for the comparison of the greatest number of participants (i.e. the combination of intervention Group A and Group B (education at birth) compared with intervention group C and control group D (no education)).

Table C: Vaccination status outcome features

aSecondary vaccination outcome reported by study but not used in meta‐analysis

bAdditional time point reported by study but not used in meta‐analysis

Knowledge or understanding of vaccination

Five studies contributed usable data for this outcome. The final assessment was at three or six months post‐intervention. Wood 1998 measured knowledge at 15 months postpartum, but this was a multi‐session intervention that included a variable number of home visits, and the time between final session and outcome assessment was not stated. All data were collected through pre‐ and post‐tests (written or oral); higher scores corresponded to greater knowledge.

Jackson 2011 measured knowledge of MMR on a scale from 0 to 11. Quinlivan 2003 measured knowledge of the immunisation schedule using a scale ranging from 0 to 10. Saitoh 2013 and Saitoh 2017 both measured knowledge in similar ways. The knowledge assessment in Saitoh 2017 comprised four questions about vaccine‐preventable diseases, five basic immunisation knowledge questions, and a question asking participants to identify four recommended vaccines from a list of 12 (combined for a total score of 13). We received clarification from the study authors around the scales used in Saitoh 2013. Participants in this study were scored separately for correct identification of vaccine‐preventable diseases (0 to 13 points) and basic immunisation knowledge (0 to 10). We combined the scores for these two tests in our analysis ‐ this is explored further in the Effects of interventions section. Saitoh 2013 also included a self‐reported knowledge test, which was not an objective measure of knowledge and was not included in this review. Wood 1998 used two tests to measure knowledge of the immunisation schedule and contraindications. Data from the immunisation schedule test were reported inconsistently, so for the purposes of this review, only scores relating to knowledge of contraindications for immunisation could be used. The test featured three questions with a scale of 0 to 3.

Two studies did not contribute usable data on knowledge or understanding to the review (Bjornson 1997; Hu 2017), and the data from Quinlivan 2003 were skewed, so were not included in the meta‐analysis. Bjornson 1997 assessed knowledge of vaccines, infectious diseases, contraindications and the immunisation schedule using a 16‐question test, administered immediately before and directly following the delivery of the intervention session. The authors reported the percentage of participants who got each of the 16 questions correct on each test, but did not provide the mean scores of the intervention and control clusters, so the data could not be used in this review. We contacted the study authors, but they were unable to provide additional data, due to the age of the study.

In Hu 2017, the authors stated that they measured participant knowledge of the vaccine schedule and vaccine policy six months after the intervention was delivered. Participants were asked to correctly select 10 vaccines for a total of five points, and correct vaccine policy answers were worth up to six points. The aggregated knowledge score ranged from 0 to 11 and was dichotomised as seven points or higher, or less than seven points. However, the supplemental material provided with the published trial suggested that the knowledge test was not an objective measure of knowledge. The list of vaccines included only ten, and the answer options were 'Yes, I know' or 'I do not know'. These were also the answer options for the vaccine policy questions, e.g. 'Do you know the location for immunisation registry?' (Yes I know / I do not know). We contacted the authors to clarify the intent of these scales and to confirm that there had been no errors of translation, but we were unable to reach them. We determined that this measurement scale could not objectively assess knowledge, so we did not include these data in the review.

Table D: Knowledge or understanding outcome features

aAdditional time point reported by study but not used in meta‐analysis

Attitudes or beliefs

Three studies measured parent attitudes or beliefs towards vaccines in general (Saitoh 2013; Saitoh 2017), or towards MMR in particular (Jackson 2011). The attitude assessment tools for Saitoh 2013 and Saitoh 2017 were very similar, and were both based on aspects of the Health Belief Model and the Integrated Behavioral Model. The tool measured eight separate attitude outcomes, using 21 statements (Saitoh 2013), or 20 statements (Saitoh 2017). The eight outcome categories were: perceived severity, susceptibility, benefits, barriers, self‐efficacy, behavioural control, and injunctive and descriptive social norms. Participants rated each statement on a five‐point Likert scale from one (strongly disagree) to five (strongly agree). The tool was translated from English to Japanese. The translation was confirmed and the tool piloted prior to use, but was not described as validated.

Jackson 2011 measured three attitude outcomes: attitude towards MMR, necessity of MMR beliefs, and concern about MMR beliefs. The tool assessed attitude towards MMR with one question, scored on a seven‐point scale ('For me to give my child the combined MMR vaccine at the recommended ages would be ...' 1 extremely bad to 7 extremely good). This item had demonstrated reliability and validity. The authors adapted an existing questionnaire (Beliefs about Flu Vaccination Questionnaire) to assess beliefs, though this tool was not validated for MMR (Bekker 2003). Parents recorded their necessity beliefs using four items (e.g. 'Without the combined MMR vaccine, my child could get very ill from measles, mumps or rubella'). Concern beliefs were assessed with another four items (e.g. 'Giving my child the combined MMR vaccine worries me'). These items were scored on five‐point scales. Scores were summed for each type of belief, for a total score of 4 to 20 for necessity and for concern (higher scores indicated stronger beliefs about the necessity for, or concern about, MMR).

Although three studies measured attitudes or beliefs related to vaccination, these were measured in a variety of ways both within each study and across studies (Table 3). We reviewed the descriptions of the outcome measures to identify the most similar attitude outcome across studies: perceived severity (Saitoh 2013; Saitoh 2017) and necessity beliefs (Jackson 2011).

Table E: Attitudes or beliefs outcome features

aAdditional time point reported by study but not used in meta‐analysis

Intention to vaccinate

Two studies measured parents' intention to vaccinate at three months post‐intervention (Jackson 2011; Saitoh 2013). Both studies used pre‐ and post‐intervention questionnaires or surveys to record the data. In Jackson 2011, parents reported their intended choice about vaccinating their child with the first or second dose of MMR. They rated three items on a seven‐point scale, and the scores were averaged to produce a score from 0 to 7 (from 'do not intend to vaccinate', to 'do intend to vaccinate'). These items had demonstrated reliability and validity, according to the authors. In Saitoh 2013, parents answered one question about their intention to vaccinate using a four‐point scale (1 = no, 2 = undecided, 3 = yes, for a specific vaccine, and 4 = yes).

Table F: Intention to vaccinate outcome features

aAdditional time point reported by study but not used in meta‐analysis

Adverse effects

Anxiety associated with the intervention was the only adverse event measured in any studies. Anxiety was measured by Jackson 2011 at one week post‐intervention and three months post‐intervention (final follow‐up). The scale included six items (e.g. 'I feel calm' or 'I am tense'), each scored on a four‐point scale, from 'not at all', to 'very much'. Positive items were reversed, and the scores for all six items were combined and then multiplied by 20/6 for a total score of 20 (very low anxiety) to 80 (very high anxiety). The authors report that a normal score was 34 to 36.

Secondary outcomes

No studies measured parent experience of the intervention.

The cost of implementing the intervention was measured by Wood 1998. See Effects of interventions for further details about the cost‐effectiveness calculations used.

Excluded studies

We excluded 29 studies at the full‐text stage (see 'Characteristics of excluded studies' table). The reasons for exclusion were:

1. the study was not an RCT or cluster‐RCT (N = 10);

2. the intervention was a maternal outreach or support intervention, where the immunisation content was not specified or consistently delivered (N = 5);

3. the study did not report on a face‐to‐face information or educational intervention (N = 5);

4. the face‐to‐face intervention was part of a multi‐component intervention or a mass media campaign, in which the effect of any face‐to‐face information or education could not be isolated (N = 4);

5. the intervention was not targeted to parents (N = 4); or

6. the intervention was not relevant to immunisation (N = 1).

One study included in the original review was excluded from this update, as it was a maternal outreach or support intervention with unclear immunisation content (one of the five studies excluded for reason 2, above; Bartu 2006).

Risk of bias in included studies

The risk of bias for all included studies is summarised in Figure 2 and Figure 3.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies

Allocation

We determined a priori that sequence generation and allocation concealment were the most significant and influential risk of bias attributes. We judged nine out of ten studies at low risk of bias for sequence generation, while Jackson 2011 was unclear. For allocation concealment, three were at high risk (Usman 2009; Usman 2011; Wood 1998) and we judged one as at unclear risk (Hu 2017). Through contact with study authors, we confirmed that appropriate allocation concealment had been performed in one study (Saitoh 2013).

Blinding

Due to the overt nature of face‐to‐face interventions, blinding participants and personnel was not possible in any of the included studies, and we assessed all as high risk of bias for these factors. Outcome assessors were adequately blinded in two studies (Bolam 1998; Quinlivan 2003). Assessors were not blinded in Usman 2009 or Usman 2011, but we judged the risk of bias to be low, because the only outcome assessed was receipt of vaccine, which is not a subjective outcome. The remainder were at high or unclear risk of detection bias due to lack of blinding.

Incomplete outcome data

We only assessed two studies at low risk of bias for incomplete outcome data, either because the outcome was assessed immediately following intervention delivery (Bjornson 1997), or because attrition was relatively low and the authors used an intention‐to‐treat analysis (Saitoh 2017). Two studies had a high risk of attrition bias because those lost to follow‐up were excluded from the analysis, and the dropout rates were relatively high (25% (Bolam 1998), and 32% (Hu 2017)).

We judged six studies as being at unclear risk of attrition bias: large numbers of participants failed to receive the intervention (Jackson 2011; Wood 1998); all non‐respondents were classified as not receiving the vaccine (Usman 2009; Usman 2011); substantially more participants withdrew from one group than the other without explanation (Quinlivan 2003; Saitoh 2013).

Selective reporting

We rated only one study at low risk of bias for this domain, because the outcomes planned in the trial registration record were all reported in the published study (Saitoh 2013). We rated one study at unclear risk of bias because the trial registration record included the proposed outcome of cost, which was not reported in the published study (Saitoh 2017). All other studies were at unclear risk of bias for this domain because protocols or trial registration records were not available.

Other potential sources of bias

We judged four studies to be at low risk of other bias due to low risk of contamination and comparability of groups at baseline (Bolam 1998; Hu 2017; Saitoh 2013; Saitoh 2017).

The authors of one cluster‐RCT did not account for the effects of clustering in the analysis, so we rated this study as high risk of bias for this attribute (Bjornson 1997). Two studies reported some significant baseline demographic differences between the intervention and control groups, for which we rated them as unclear risk of bias (Quinlivan 2003; Usman 2011). In Jackson 2011, baseline characteristics were similar and contamination across study arms was unlikely, but the authors note that the leaflet they provided to all arms may have been more thorough than the actual usual care in the region, meaning they may have been comparing two different decision‐support interventions (educational session plus leaflet versus leaflet) rather than an intervention with a control. We judged the potential risk of bias arising from this as unclear. There was insufficient information to judge if other potential sources of bias were present in Usman 2009 and Wood 1998 so we also rated them at unclear risk of bias.

Selective recruitment or participants (cluster‐RCTs)

We determined two cluster‐RCTs to be at low risk of bias for selective recruitment of participants (Bjornson 1997; Jackson 2011), while one was at high risk because participants were recruited after clusters were randomised (Saitoh 2017).

Effects of interventions

See: Table 1

We present an outline of the main findings for each outcome in Table 1.

We did not find sufficient RCTs to investigate reporting bias or small‐study effects using funnel plots. However, our qualitative assessment indicated that there was low risk of reporting bias for all outcomes, as the smaller studies showed no strong evidence of an effect.

Comparison 1: Face‐to‐face interventions directed to parents versus control

Primary outcomes

Vaccination status

Seven studies compared face‐to‐face information or educational interventions with control, with the vaccination status measured either three, six, or twelve months after the intervention (Bolam 1998; Hu 2017; Jackson 2011; Saitoh 2013; Saitoh 2017; Usman 2009; Usman 2011). Face‐to‐face communication to inform or educate parents may improve vaccination status (risk ratio (RR) 1.20, 95% confidence interval (CI) 1.04 to 1.37; 3004 participants; low‐certainty evidence).

Communication interventions are frequently complex, and it can be difficult to determine whether interventions are sufficiently similar to compare. While the level of statistical heterogeneity was high (Chi² = 40.68, df = 6 (P < 0.00001); I² = 85%), we decided to pool the data for these studies, acknowledging that the length of the educational sessions and the number of vaccines delivered were potentially important differences between them. We conducted post hoc formal subgroup analyses to investigate these two potential sources of heterogeneity (Analysis 1.1 and Analysis 1.2).

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 1 Vaccination status (stratified by length).

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 2 Vaccination status (stratified by number of vaccines delivered).

For analysis stratified by session length, we categorised sessions that lasted 10 minutes or less as 'short' (Analysis 1.1; Saitoh 2013; Saitoh 2017; Usman 2009; Usman 2011), and those lasting longer than 10 minutes as 'long' (Bolam 1998; Hu 2017; Jackson 2011). In Australia, the average clinical consultation time is 15 minutes, and healthcare providers need time to both deliver the intervention and the vaccine (Britt 2016). Therefore, we determined that 10 minutes was the maximum time an intervention could take without encountering potential scheduling and reimbursement implications. The test for subgroup differences was not significant (P = 0.15). Heterogeneity of the stratified studies remained relatively high, so we were unable to conclusively state whether session length was a major contributing factor to the heterogeneity in study effects.

The second analysis grouped studies that measured receipt of a single vaccine (Analysis 1.2; Jackson 2011; Usman 2009; Usman 2011) and those that measured receipt of multiple vaccines (Bolam 1998; Hu 2017; Saitoh 2013; Saitoh 2017). This decision was based on advice from vaccination experts, and reflects the fact that receiving one vaccine is less demanding, as an outcome, than receiving several. The test for subgroup differences was significant (P = 0.04). There was no appreciable difference in heterogeneity.

Knowledge or understanding of vaccination

Moderate‐certainty evidence from four studies (657 participants) suggested that face‐to‐face information or education probably improved parent knowledge slightly, compared with control (standardised mean difference (SMD) 0.19, 95% CI 0.00 to 0.38; Analysis 1.3; Jackson 2011; Saitoh 2013; Saitoh 2017; Wood 1998). Knowledge was measured by two separate scales in Saitoh 2013 (knowledge of vaccine‐preventable diseases and basic immunisation knowledge), which we combined into a single score by summing the mean scores from each scale and calculating revised standard deviation (SD) by squaring the SD for each scale, summing them and taking the square root. Statistical heterogeneity between these studies was low (Chi² = 3.86, df = 3 (P = 0.28); I² = 22%).

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 3 Knowledge.

We were unable to include the outcome data from Quinlivan 2003 in our meta‐analysis because they were given as medians rather than means. Contact with the authors confirmed that this was because the data were skewed. In the published article, the authors reported that there were no significant differences between knowledge scores of the intervention and control groups at the antenatal or postnatal assessments (mean difference (MD) 0.85, 95% CI: ‐0.06 to 1.76).

Attitudes or beliefs

Three studies (292 participants) reported data on several measures of attitudes or beliefs. For the purpose of this review, we selected the most comparable measures of attitudes across the studies ‐ two on perceived severity of vaccine‐preventable diseases (Saitoh 2013, Saitoh 2017), and one on beliefs about the necessity of the MMR vaccine (Jackson 2011). Face‐to‐face information or educational interventions may lead to little or no change in parent attitudes or beliefs about disease severity or vaccine necessity (SMD 0.03, 95% CI ‐0.20 to 0.27; Analysis 1.4; low‐certainty evidence). Heterogeneity was not detected (Chi² = 0.08, df = 2 (P = 0.96); I² = 0%), but all were small studies with a small combined total number of participants.

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 4 Attitudes ‐ necessity.

Intention to vaccinate

Low‐certainty evidence from two studies (179 participants) suggests that face‐to‐face information or education delivered to parents may slightly increase parents' intention to vaccinate (SMD 0.55, 95% CI 0.24 to 0.85; Analysis 1.5; Jackson 2011; Saitoh 2013). Heterogeneity was not detected (Chi² = 0.81, df = 1 (P = 0.37); I² = 0%).

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 5 Intention to vaccinate.

Adverse effects (anxiety)

Only one study (90 participants) measured this outcome (Jackson 2011). Face‐to‐face information or educational interventions may lead to little or no change in parents' anxiety (MD ‐1.93, 95% CI ‐7.27 to 3.41; low‐certainty evidence; Analysis 1.6).

Analysis

Comparison 1 Face‐to‐face education versus control or non‐face‐to‐face education (all), Outcome 6 Adverse effects (anxiety).

Secondary outcome

Cost

Only one included study reported data on costs of implementing an intervention (Wood 1998). The certainty of this evidence was judged to be very low, and consequently we are very uncertain of the effects of the intervention on cost outcomes. This study reported a full cost‐effectiveness analysis of a case management intervention to promote childhood immunisation, compared with usual practice. Total costs were estimated, based on costs of personnel, supplies, travel, office space, and orientation costs of the intervention only. Costs calculated per individual took account of indirect case management costs (based on the frequency and time taken for case managers to complete client‐related contact tasks) in the same proportion as direct costs incurred by the intervention.

The total cost of the intervention was calculated to be USD 293,662 (price year not stated). For the intervention group (N = 185), the mean cost per participant was calculated as USD 1587, and the additional cost of bringing one non‐immunised child fully up‐to‐date with immunisations by one year was estimated to be USD 12,022. This study did not consider potential costs arising from non‐immunisation (e.g. costs of contracting a disease).

Analysis was also conducted on a high‐risk subgroup of those receiving the intervention, defined by the authors as those children who had received only three or fewer well‐child visits (of a total of five visits). In this subgroup (n = 86), the mean cost per participant was estimated as USD 1273, with the additional cost of bringing one non‐immunised child fully up to date with immunisations by one year calculated as USD 4546.

The study authors reported resource use, but this was expressed in terms of monetary costs rather than physical resource quantities. They noted that the cost‐effectiveness data may underestimate the true cost‐effectiveness of the intervention, due to start‐up and evaluation costs associated with the delivery of the intervention over a short time period. However, there are several factors that may limit the conclusions that can be drawn from this study: the cost‐effectiveness analysis did not consider effects of the intervention on subsequent care, nor of changes to the costs of usual practice over time. Cost data were presumably reported in US dollars, with no information provided on the price year. Given that the study was published in 1998, the costs and cost‐effectiveness of such a case management intervention may be substantially different in today's terms. All outcomes and costs associated with the study were measured at 12 months, with no longer‐term data reported, which limits the conclusions that can be drawn. Finally, the intervention delivered by this study was much more complex, and therefore potentially resource‐intensive, than many of the other interventions included in this review.

Parent experience of the intervention

No included studies reported this outcome.

Comparison 2: Face‐to‐face intervention A versus face‐to‐face intervention B

No included studies reported this comparison.

Discussion

Summary of main results

This systematic review found some evidence, of low to moderate certainty, suggesting that face‐to‐face interventions to inform or educate parents about childhood vaccination may improve children's vaccination status, probably slightly improves parents' knowledge or understanding of vaccination, and may slightly increase intention to vaccinate. These interventions may lead to little or no difference in parent attitudes or anxiety related to the intervention. There was uncertain evidence related to the cost of implementing interventions, and no evidence available from the included studies regarding parent experience of the intervention.

Overall completeness and applicability of evidence

This review used a comprehensive search strategy, which followed Cochrane search methods, and was not restricted by language or publication status. We included only randomised controlled trials (RCT), though there tend to be fewer trials in this area than there are for clinical or biomedical topics, due to the challenges of conducting RCTs of complex public health interventions. This meant that relatively few studies met the inclusion criteria, but by definition, those that did should have been of relatively high quality compared to other study designs (Higgins 2011). Implementing communication interventions can be costly and time‐consuming, so it is important for policy makers and programme managers to be able to base their decisions on rigorous, high‐quality evidence, wherever possible. We excluded quasi‐RCTs, but recognise that excluding studies for inadequate randomisation can be seen as a form of research waste. Future updates of this review may consider quasi‐RCTs and additional study designs as eligible for inclusion.

The global applicability of the evidence included in this review is uncertain. Two studies were conducted in Japan, where some vaccines are required and funded by the government, but some are not (Saitoh 2013; Saitoh 2017). The coverage rate for those vaccines that are not required and funded is substantially lower, in part because this policy implies that these vaccines are optional, or less important. In this context, an intervention that increases awareness by providing information and education may show greater effect than in a country where awareness is high, but vaccine hesitancy is a problem (e.g. the UK, where Jackson 2011 took place). Three of the ten included studies were conducted in low and middle income countries (LMIC), which may also have implications for the applicability of the findings.

We did not include multi‐component interventions where the effects of the face‐to‐face intervention could not be isolated, which resulted in the exclusion of many studies that included a face‐to‐face element. It is possible that face‐to‐face interventions may be more or less effective, depending on the additional interventions with which they are combined. However, assessing the effects of a single intervention is important to allow decision makers to determine whether it is worthwhile, cost‐effective, or both, to implement a particular intervention alone; or whether it may be beneficial to combine interventions, and if so, which components to combine (Ryan 2014).

All of the new studies included in this update measured a much broader range of outcomes than those in the original review, which is encouraging, as it suggests increased recognition of the importance of considering intermediate outcomes, like knowledge, attitudes, and intention to vaccinate. In the original review, only two studies measured knowledge, and none measured any other intermediate outcomes. Unpacking the effects of complex interventions requires the measurement of a range of outcomes that are able to detect potential impacts along the causal chain (Breuer 2015; Craig 2008; Moore 2015). Measuring outcomes, such as knowledge, attitudes, and intention to vaccinate ‐ in addition to endpoint outcomes related to vaccination status ‐ is necessary to determine which parts of complex communication interventions are effective, and to identify whether interventions are impacting vaccine hesitancy. While the breadth of outcomes was greater in the newer studies, there were still some issues. The tools and scales used to measure attitudes were highly variable, making it difficult to compare the data for this outcome across studies. Also, no studies assessed parents' experiences of the intervention, such as satisfaction with, or acceptability of the intervention. Qualitative research has highlighted that parents' perceptions about their communication encounters can impact their decisions around vaccination (Ames 2017; Brown 2010). Similarly, cost is a critical factor affecting implementation decisions made by policymakers and programme managers, but cost was only reported in one study (Wood 1998). As this study was from 1998, and was limited to a specific complex intervention (case management) in a low‐income population in a high‐income country, it is unlikely to be generalisable to other settings.

Quality of the evidence

The certainty of the evidence was moderate to low for each outcome. All studies had limitations in design. We downgraded evidence where the contributing studies were at high or unclear risk of bias for sequence generation (Jackson 2011), or allocation concealment (Hu 2017; Usman 2009; Usman 2011; Wood 1998).

We also downgraded the certainty of the evidence for vaccination status, due to inconsistency, which was clear from the high level of statistical heterogeneity. The certainty of the evidence for intention to vaccinate and adverse effects was downgraded for imprecision, due to the wide confidence intervals for the included studies. We downgraded the certainty of the evidence for attitudes due to indirectness, because the specific measures for this outcome (perceived diseases severity and vaccine benefits) were only part of what could be measured, and what was relevant to parents and other decision makers. We did not downgrade any outcomes for issues of publication bias.

Potential biases in the review process

We pooled the results of studies reporting vaccination status, despite high levels of statistical heterogeneity. This may have introduced some bias because the actual effect size might be substantially larger or smaller than that of the pooled (mean) result. We conducted post hoc formal subgroup analyses to investigate two potential implementation‐relevant sources of this heterogeneity (length of intervention session and number of vaccines received). However, heterogeneity remained largely unexplained in both cases. As more studies are added in future updates of this review, we will reconsider this analysis and investigate the effects of relevant explanatory factors identified from the existing research.

Another possible source of bias is our selection of comparable measures of attitudes or beliefs. The data used for the purposes of analysis were selected from more than one measurement of attitudes and beliefs available per included trial. We cannot rule out the possibility that other researchers might choose alternative measurements from the same studies, and so reach different conclusions about the effects of the intervention on this outcome. This is relatively likely, as there is an absence of agreement over the most appropriate ways of measuring attitudes and beliefs in the field of vaccination.

All other methods and literature searching for this update did not deviate from the processes outlined in the original review, and should be relatively free from bias.

Agreements and disagreements with other studies or reviews

The findings of this review are largely consistent with those of other recent reviews, which suggest that educational interventions, face‐to‐face communication, or a combination, may have some positive impact on vaccination status and parent knowledge or attitudes. The Cochrane Review of interventions for improving childhood vaccination coverage in LMICs assessed 14 studies, six of which evaluated the effects of health education. The review authors found moderate‐certainty evidence that health education at village meetings or at home probably improved coverage (Oyo‐Ita 2016). Another Cochrane Review looked at community‐aimed interventions to inform or educate about early childhood vaccination. The authors included two studies, which found that community‐aimed interventions probably increased vaccination uptake in some circumstances, and may have improved knowledge and attitudes towards vaccination (Saeterdal 2014).

Two non‐Cochrane reviews considered a broader range of intervention types, but also highlighted the relevance of face‐to‐face educational interventions. According to Jarrett 2015, who reviewed strategies for addressing vaccine hesitancy, dialogue‐based interventions were the most commonly used. Harvey 2015 assessed parental reminder, recall, and educational interventions, finding that discussion‐based education was more effective than written education.

One recent review aimed to identify the effectiveness of specific provider‐parent communication techniques, but found insufficient high‐quality evidence on which to draw a conclusion (Connors 2017). Our review was similarly limited by the shortage of trial evidence on this topic.

In future updates of this review, we may compare our findings with those of RCTs involving face‐to‐face interventions for recommended adult vaccinations, to provide relevant context and insight.

Authors' conclusions

Implications for practice

Face‐to‐face communication about childhood vaccination is very common, and usually addresses a lack of acceptance or awareness of vaccination. It takes place in many settings, and is delivered by a range of people around the world; sometimes it is planned and formalised, other times it is a casual or informal discussion. It is important to consider this intervention against outcomes beyond the behavioural (e.g. vaccination status). Explanation and understanding of healthcare procedures form the basis of informed consent, so discussions about vaccination should and will continue to take place, regardless of the findings of research evidence about their effectiveness. However, given the ubiquity of this communication method, healthcare providers and practitioners should be encouraged to know that face‐to‐face information or education about childhood vaccination may have positive effects.

This review suggests that immunisation‐focused educational messages may be sufficient to improve vaccination coverage and knowledge.

There may be some populations or healthcare contexts in which face‐to‐face interventions may be more successful than others. The included studies did not specifically describe the hesitancy of the targeted populations and did not thoroughly explore the intervention's mechanism of effect, so it was unclear how effective information or educational interventions may be when hesitancy is the primary barrier. It is possible that these interventions may be more effective where awareness or understanding of vaccination is identified as a barrier (e.g. where people are unaware of new or optional vaccines). There were several studies that showed significant improvements in vaccination status, but the evidence across more diverse settings and populations is unclear at this time. When implementing such interventions, it is vital to understand what specific barriers to vaccination exist in that population, so their content can sufficiently target that barrier.

Implications for research

Vaccine programme managers, policy makers, and other decision makers need high‐quality randomised trial evidence on the effects of face‐to‐face information and educational interventions for parents. The current low‐ to moderate‐certainty evidence was provided by a small number of trials, conducted in high‐ and low‐income settings.

No included studies evaluated the effects of different types or styles of messaging, such as presumptive versus participatory, and how they affected different groups or levels of hesitancy. There is considerable interest in identifying the most effective way for healthcare providers to communicate with parents, but trial evidence remains limited. To date, the effects of physician communication styles have only been tested in one RCT, which focused on HPV rather than childhood vaccines (Brewer 2017), and a cluster‐RCT, which evaluated a physician communication‐training intervention (Henrikson 2015). Further RCT evidence in this area is critical, as healthcare providers are already engaged in these often‐challenging discussions with parents, and seek evidence‐based communication strategies and guidance. The participation and support of providers in future research will be essential to develop and evaluate new interventions.

One important consideration for future research aiming to improve vaccine acceptance is the need to identify and distinguish between parents who are supportive of vaccination, and those who are hesitant or planning to delay or decline recommended childhood vaccines. Nearly all parents want and value face‐to‐face communication with their healthcare providers about vaccination, but most parents already comply with recommendations. Studies that fail to differentiate between accepting and hesitant populations may fail to find relationships between an intervention and outcomes, or may underestimate an intervention's effect size, particularly in settings with high baseline vaccination rates.

The intervention was only delivered by a peer or parent facilitator in one of the nine studies (Jackson 2011). Future studies could consider alternative settings and deliverers, particularly when targeting parents with high hesitancy or mistrust of the healthcare system.

Face‐to‐face interventions can vary significantly from short, focused educational sessions that can be easily added to an existing healthcare consultation, to longer programmes covering a range of topics, and potentially involving multiple sessions. More studies are needed to determine the relative effectiveness of each approach, and descriptions of interventions and their components must be clear and detailed. One possible method for improving intervention reporting is the Template for Intervention Description and Replication (TIDieR) checklist, which provides guidance on the information needed to sufficiently describe an intervention (Hoffman 2014).

Due to the difficulty of isolating the effects of multi‐component interventions, it may be beneficial to consider testing single interventions, or to organise trials with stepped interventions, to assess the effects of each component. The control comparison or routine care also needs to be clearly described, particularly if it includes some degree of face‐to‐face interaction. Failure of an intervention to sufficiently differentiate from usual care is a key barrier to successful implementation (May 2009).

More recent studies appear to be measuring a broader range of intermediate outcomes, including knowledge, attitudes and beliefs, and intention to vaccinate. However, there is little agreement on the most appropriate measurement method or scale to apply for many of these outcomes, so it remains difficult to compare effects across studies. Preliminary work has been undertaken to develop a core set of outcome domains to measure when evaluating the effects of vaccination communication interventions (Kaufman 2017a). The critical next step is to develop and test reliable and validated scales ‐ particularly for multi‐faceted outcomes, such as attitudes or beliefs ‐ and disseminate them widely, in order to improve consistency of outcome assessment and consensus on which outcomes most closely reflect the outcome of interest.

What's new

Acknowledgements

We would like to thank John Kis‐Rigo for developing the search strategy for this updated review.

Appendices

Appendix 1. Definitions of 'inform' and 'educate' from original 2013 review

Defining the intervention

We examined the literature to see if information was defined differently from education, as this may have affected the methods of the review. To do this, we searched the following sources: major health agency websites, grey literature reports describing immunisation campaign strategies, and literature about general patient education. We conducted a content analysis to see how these terms were used, described and defined in practice.

Our main conclusion was that there was no agreement about the difference between informing and educating. From the content analysis, four things became clear:

1. It is acknowledged that informing may be different from educating, however the ways in which they might differ are rarely explained;

2. Both of the interventions are described and operationalised in many different ways, and with varying degrees of overlap;

3. Information delivery is frequently described as a component of education, rather than an intervention in its own right;

4. interventions are not often labelled as ’informing’ or ’educating’. A plethora of terms is used to describe informing or educating interventions. For example, interpersonal communication, program communication, and behaviour change communication are all terms that can be applied to education interventions (UNICEF 2005).

There were some consistencies in the ways agencies and publications described interventions to inform and to educate, but overall, our main conclusion was that there was not sufficient agreement as to how they differed from one another. Due to a lack of detailed description, and inconsistent language, there was no reliable way to determine which type of intervention a given trial described.

The implications for our review were that we included all interventions that aimed to inform or educate, without distinguishing between these two purposes.

Our definition of the intervention

Relevant interventions are those that make consumers aware of the practical or logistical factors associated with vaccination, or seek to enable them to understand the meaning and relevance of vaccination for themselves, their family or community (Willis 2013) The goal of these interventions could be to achieve outcomes, such as improved vaccination coverage; appropriate timeliness of vaccination; or increased knowledge of vaccines, vaccine‐preventable diseases, or service delivery. Interventions may be tailored to address low literacy levels or misinformation.

Descriptions of 'inform' and 'educate' from different sources

Appendix 2. Behaviour change theories and their application to vaccination

Appendix 3. Sources searched in original review

In the original review, we searched the following databases and additional sources (Kaufman 2013).

Electronic searches

We searched the following international and regional sources:

• Cochrane Central Register of Controlled Trials (CENTRAL; 2012, issue 7) in the Cochrane Library

• MEDLINE Ovid (1946 to July 2012)

• Embase Ovid (1947 to July 2012)

• CINAHL EBSCO HOST (1981 to July 2012)

• PsycINFO Ovid (1806 to July 2012)

• Global Health (CAB; 1910 to July 2012)

• Global Health Library (WHO; includes WHOLIS, LILACS, other regional WHO databases; searched July 2012)

We tailored strategies to each database. There were no language or date restrictions.

Searching other resources

• We searched for ongoing trials in the International Clinical Trials Registry Platform (ICTRP; searched August 2012) and contacted authors to obtain further information or eligible data if available.

• We searched for grey literature in:

1. The Grey Literature Report (searched August 2012): www.nyam.org/library/online‐resources/grey‐literature‐report/

2. OpenGrey (searched August 2012): www.opengrey.eu/

• We searched the reference lists of all included papers and any key papers in the field. We also searched the ISI Web of Science (both the Social Science Citation Index and the Science Citation Index; searched September 2012) and Google Scholar (searched September 2012) for papers that cited the studies included in the review. We contacted authors of included studies and vaccination experts from the COMMVAC project advisory group and asked for additional references.

• We also asked authors of included studies to identify any economic evaluations conducted alongside the studies.

Appendix 4. Glossary

Appendix 5. CENTRAL search strategy

3 July 2017

ID Search

#1 [mh communication]

#2 (*communicat* or messag* or face‐to‐face or verbal* or nonverbal* or written or writing or read* or language* or speech* or speak* or spoken or talk* or conversation* or listen* or negotiat* or narrat* or dialog* or question* or promot* or market* or adverti* or persua* or signage* or cartoon* or humo* or music* or interpreter* or translator*):ti,ab,kw

#3 readability or intelligibility or credibility

#4 trust* or truth* or deceiv* or deception

#5 [mh "interpersonal relations"]

#6 ("human relation*" or interpersonal):kw

#7 [mh "hospital‐patient relations"]

#8 [mh "community‐institutional relations"]

#9 (professional or physician or doctor or clinician or nurse or provider or practitioner or pediatrician) near/1 (patient or client or family or parent)

#10 (improv* or increas* or enhanc* or rais*) near/3 (knowledge or understanding or comprehension or aware*)

#11 (health or patient* or client*) near/2 knowledge

#12 (educat* or teach* or learn* or instruct* or train* or coach*):ti,ab,kw

#13 (community or family or office or work* or school or faith or church) next based

#14 information* near/1 (service* or disseminat* or seek* or transfer* or campaign* or provid* or provision or aid* or material* or sheet* or pack*)

#15 (patient* or client* or health or medical or written or print* or visual* or provid* or present* or vaccin* or immuni*) near/2 inform*

#16 (oral or text or data or dynamic or numerical or statistical or visual or graphic* or pictorial or audio*) next (format* or presentation* or display*)

#17 counsel* or advis* or advice* or "social support" or psychosocial or ((social or pastoral or spiritual) next care)

#18 (support* or peer*) near/2 (intervention* or group* or program* or project*)

#19 (social or community) near/2 network*

#20 ((print* next (material or media or feedback or based)) or paper‐based or postal or mail* or letter* or correspondence or (paper near/2 pen*) or publication* or newsletter* or brochure* or booklet* or pamphlet* or leaflet* or flyer* or handout* or poster* or billboard* or illustrat* or picture* or pictogram* or graphic* or icon*):ti,ab,kw

#21 (home* near/3 visit*) or interview* or session* or lecture* or meeting* or presentation*

#22 cultural* near/3 (service* or care or intervention* or appropriate* or sensitiv*)

#23 [mh "informed consent"]

#24 "parental consent"

#25 informed next (consent or choice* or decision*)

#26 "choice behavior":kw

#27 decision next (making or support* or aid* or tool*)

#28 (patient or person or family or client) next (cent*red or focus*ed or oriented)

#29 (shared or joint) near/3 decision*

#30 {or #1‐#29}

#31 [mh immunization]

#32 [mh vaccines]

#33 (immuniz* or immunis* or immunotherap* or *vaccin* or in*oculat* or *prophyla*):ti,ab,kw

#34 #31 or #32 or #33

#35 #30 and #34

#36 [mh child]

#37 [mh infant]

#38 [mh parents]

#39 perinatal or peri‐natal or postnatal or post‐natal

#40 (child* or infan* or toddler* or newborn or neonat* or baby or babies or preschool* or pre‐school* or kindergarten* or boy* or girl* or schoolchild* or pediatric* or paediatric* or parent* or mother* or father* or maternal or paternal):ti,ab,kw

#41 {or #36‐#40}

#42 #35 and #41 Publication Year from 2012 to 2017

Appendix 6. MEDLINE Ovid search strategy

1. immunotherapy/
2. exp immunization/
3. Immunization Programs/
4. exp vaccines/
5. (vaccin* or revaccinat* or immuniz* or immunis* or immunother* or inoculat* or innoculat* or prophyla* or immunoprophyla*).ti,ab,kf.
6. or/1‐5
7. exp child/
8. exp infant/
9. exp perinatal care/
10. exp parents/
11. (child* or infan* or toddler* or newborn or neonat* or baby or babies or preschool* or pre‐school* or kindergarten* or boy* or girl* or schoolchild* or pediatric* or paediatric* or parent* or mother* or father* or maternal or paternal).mp.
12. or/7‐11
13. 6 and 12
14. exp communication/
15. (communicat* or messag* or face to face or verbal* or nonverbal* or written or writing or reading or language* or speech* or speak* or spoken or talk* or conversation* or listen* or negotiat* or narrat* or dialog* or question* or promot* or marketing or adverti* or persua* or signage* or cartoon* or humo?r* or music* or interpreter* or translator*).mp.
16. (readability or intelligibility or credibility).mp.
17. (trust* or truth* or deceiv* or deception or misinform*).mp.
18. exp interpersonal relations/
19. hospital patient relations/
20. community institutional relations/
21. ((professional or physician or doctor or clinician or nurse or provider) adj1 (patient or client or family)).mp.
22. ((improv* or increas* or enhanc* or rais*) adj3 (knowledge or understanding or comprehension or aware*)).ti,ab,kf.
23. ((health or patient* or client*) adj2 knowledge).mp.
24. (educat* or teach* or instruct* or train* or coach* or learn*).mp.
25. ((community or family or office or work* or school or faith or church) adj based).ti,ab,kf.
26. (information* adj (service* or disseminat* or seek* or transfer* or campaign* or provid* or provision or aid or material* or sheet* or pack*)).mp.
27. ((patient or client or health or medical or written or print* or visual* or provid* or present* or vaccin* or immuni*) adj2 inform*).mp.
28. ((oral or text* or data or numerical or statistical or visual or graphic*) adj (format* or presentation* or display*)).mp.
29. (counsel* or advis* or advice* or social support or psychosocial or ((social or pastoral or spiritual) adj care)).mp.
30. ((support or peer) adj2 (intervention* or group* or program*)).mp.
31. ((social or community) adj2 network*).mp.
32. ((print* adj (material* or based or media)) or paper‐based or (paper adj1 pen*) or publication* or newsletter* or brochure* or booklet* or pamphlet* or leaflet* or flyer* or handout* or poster* or illustrat* or picture* or pictogram*).mp.
33. ((home* adj3 visit*) or interview* or session* or lecture* or meeting* or presentation*).mp.
34. (cultural* adj3 (service* or care or intervention* or appropriate* or sensitiv*)).mp.
35. choice behavior/
36. (decision adj (making or support or aid*)).mp.
37. exp informed consent/
38. (informed adj (consent or choice* or decision*)).ti,ab,kf.
39. ((patient or person or family or client) adj (cent*red or focus*ed or oriented)).mp.
40. or/14‐39
41. 13 and 40
42. randomized controlled trial.pt.
43. controlled clinical trial.pt.
44. randomized.ab.
45. placebo.ab.
46. drug therapy.fs.
47. randomly.ab.
48. trial.ab.
49. groups.ab.
50. or/42‐49
51. 41 and 50
52. limit 51 to yr="2012‐current"
53. 51 and (201207* or 201208* or 201209* or 201210* or 201211* or 201212* or 2013* or 2014* or 2015* or 2016* or 2017*).ed,ep,dc.
54. 52 or 53

Appendix 7. Embase search strategy

1. exp immunization/
2. exp Immunotherapy/
3. exp vaccine/
4. (vaccin* or revaccinat* or immuniz* or immunis* or immunother* or inoculat* or innoculat* or prophyla* or immunoprophyla*).ti,ab,kw.
5. or/1‐4
6. exp child/
7. exp perinatal care/
8. exp parent/
9. (child* or infan* or toddler* or newborn or neonat* or baby or babies or preschool* or pre‐school* or kindergarten* or boy* or girl* or schoolchild* or pediatric* or paediatric* or parent* or mother* or father* or maternal or paternal).mp.
10. or/6‐9
11. 5 and 10
12. exp interpersonal communication/
13. (communicat* or messag* or face to face or verbal* or nonverbal* or written or writing or reading or language* or speech* or speak* or spoken or talk* or conversation* or listen* or negotiat* or narrat* or dialog* or question* or promot* or marketing or adverti* or persua* or signage* or cartoon* or humo?r* or music* or interpreter* or translator*).mp.
14. (readability or intelligibility or credibility).mp.
15. (trust* or truth* or deceiv* or deception or misinform*).mp.
16. exp human relation/
17. ((professional or physician or doctor or clinician or nurse or provider) adj1 (patient or client or family)).mp.
18. ((improv* or increas* or enhanc* or rais*) adj3 (knowledge or understanding or comprehension or aware*)).ti,ab,kw.
19. (educat* or teach* or instruct* or train* or coach* or learn*).mp.
20. ((community or family or office or work* or school or faith or church) adj based).ti,ab,kw.
21. ((health or patient* or client*) adj2 knowledge).mp.
22. exp information/
23. (information* adj (service* or disseminat* or seek* or transfer* or campaign* or provid* or provision or aid or material* or sheet* or pack*)).mp.
24. ((patient or client or health or medical or written or print* or visual* or provid* or present* or vaccin* or immuni*) adj2 inform*).mp.
25. ((oral or text* or data or numerical or statistical or visual or graphic*) adj (format* or presentation* or display*)).mp.
26. (counsel* or advis* or advice* or social support or psychosocial or ((social or pastoral or spiritual) adj care)).mp.
27. ((support or peer) adj2 (intervention* or group* or program*)).mp.
28. ((social or community) adj2 network*).mp.
29. ((print* adj (material* or based or media)) or paper‐based or (paper adj1 pen*) or publication* or newsletter* or brochure* or booklet* or pamphlet* or leaflet* or flyer* or handout* or poster* or illustrat* or picture* or pictogram*).mp.
30. ((home* adj3 visit*) or interview* or session* or lecture* or meeting* or presentation*).mp.
31. (cultural* adj3 (service* or care or intervention* or appropriate* or sensitiv*)).mp.
32. (decision adj (making or support or aid*)).mp.
33. parental consent/
34. (informed adj (consent or choice* or decision*)).mp.
35. ((patient or person or family or client) adj (cent*red or focus*ed or oriented)).mp.
36. or/12‐35
37. 11 and 36
38. randomized controlled trial/
39. controlled clinical trial/
40. single blind procedure/ or double blind procedure/
41. crossover procedure/
42. random*.tw.
43. placebo*.tw.
44. ((singl* or doubl*) adj (blind* or mask*)).tw.
45. (crossover or cross over or factorial* or latin square).tw.
46. (assign* or allocat* or volunteer*).tw.
47. or/38‐46
48. 37 and 47
49. limit 48 to yr="2012‐current"
50. 48 and (201207* or 201208* or 201209* or 201210* or 201211* or 201212* or 2013* or 2014* or 2015* or 2016* or 2017*).dc.
51. 49 or 50

Appendix 8. CINAHL search strategy

S1 child* or infan* or toddler* or newborn or neonat* or baby or babies or preschool* or pre‐school* or kindergarten* or boy* or girl* or schoolchild* or pediatric* or paediatric* or parent* or mother* or father* or maternal or paternal
S2 perinatal or peri‐natal or postnatal or post‐natal
S3 s1 or s2
S4 mh immunization+
S5 mh vaccines+
S6 immuniz* or immunis* or immunotherap* or vaccin* or revaccinat* or inoculat* or innoculat* or prophyla* or immunoprophyla*
S7 s4 or s5 or s6
S8 s3 and s7
S9 communicat* or messag* or face‐to‐face or verbal* or nonverbal* or written or writing or read* or language* or speech* or speak* or spoken or talk* or conversation* or listen* or negotiat* or narrat* or dialog* or question* or promot* or market* or adverti* or persua* or signage* or cartoon* or humo* or music* or interpreter* or translator*
S10 readability or intelligibility or credibility or trust* or truth* or deceiv* or deception or misinformation
S11 (professional or physician or doctor or clinician or nurse or provider or practitioner or pediatrician) N1 (patient or client or family or parent)
S12 (improv* or increas* or enhanc* or rais*) N3 (knowledge or understanding or comprehension or aware*)
S13 (health or patient* or client*) N2 knowledge
S14 educat* or teach* or learn* or instruct* or train* or coach*
S15 (community or family or office or work* or school or faith or church) N1 based
S16 information* N1 (service* or disseminat* or seek* or transfer* or campaign* or provid* or provision or aid* or material* or sheet* or pack*)
S17 (patient* or client* or health or medical or written or print* or visual* or provid* or present* or vaccin* or immuni*) N2 inform*
S18 (oral or text or data or dynamic or numerical or statistical or visual or graphic* or pictorial or audio*) N1 (format* or presentation* or display*)
S19 counsel* or advis* or advice* or "social support" or psychosocial or ((social or pastoral or spiritual) N1 care)
S20 (support* or peer*) N2 (intervention* or group* or program* or project*)
S21 (social or community) N2 network*
S22 (print* N1 (material or media or feedback or based)) or paper‐based or postal or mail* or letter* or correspondence or (paper N2 pen*) or publication* or newsletter* or brochure* or booklet* or pamphlet* or leaflet* or flyer* or handout* or poster* or billboard* or illustrat* or picture* or pictogram* or graphic* or icon*
S23 (home* N3 visit*) or interview* or session* or lecture* or meeting* or presentation*
S24 cultural* N3 (service* or care or intervention* or appropriate* or sensitiv*)
S25 (informed N1 (consent or choice* or decision*)) or "parental consent" or (decision N1 (making or support* or aid* or tool*))
S26 (patient or person or family or client) N1 (cent*red or focus*ed or oriented)
S27 s9 or s10 or s11 or s12 or s13 or s14 or s15 or s16 or s17 or s18 or s19 or s20 or s21 or s22 or s23 or s24 or s25 or s26
S28 s8 and s27
S29 "randomi?ed controlled trial" or PT randomized controlled trial
S30 PT Clinical Trial
S31 MH Clinical Trials+
S32 MH Random Assignment
S33 MH Placebos
S34 MH Quantitative Studies
S35 AB (random* or trial or placebo*) or TI (random* or trial or placebo*)
S36 AB (singl* or doubl* or tripl* or trebl*) and AB (blind* or mask*)
S37 TI (singl* or doubl* or tripl* or trebl*) and TI (blind* or mask*)
S38 S29 or S30 or S31 or S32 or S33 or S34 or S35 or S36 or S37
S39 s28 and s38
S40 PY 2012‐2017
S41 s39 and s40
S42 s41 Limiters ‐ Exclude MEDLINE records

Appendix 9. PsycINFO search strategy

1. exp immunotherapy/
2. (vaccin* or revaccinat* or immuniz* or immunis* or immunother* or inoculat* or innoculat* or prophyla* or immunoprohyla*).ti,ab,id.
3. or/1‐2
4. exp parents/
5. (child* or infan* or toddler* or newborn or neonat* or baby or babies or preschool* or pre‐school* or kindergarten* or boy* or girl* or schoolchild* or pediatric* or paediatric* or parent* or mother* or father* or maternal or paternal).mp.
6. or/4‐5
7. 3 and 6
8. exp interpersonal communication/
9. exp verbal communication/
10. exp nonverbal communication/
11. (communicat* or messag* or face to face or verbal* or nonverbal* or written or writing or reading or language* or speech* or speak* or spoken or talk* or conversation* or listen* or negotiat* or narrat* or dialog* or question* or promot* or marketing or adverti* or persua* or signage* or cartoon* or humo?r* or music* or interpreter* or translator*).mp.
12. (readability or intelligibility or credibility).mp.
13. (trust* or truth* or deceiv* or deception or misinform*).mp.
14. interpersonal.mp.
15. ((professional or physician or doctor or clinician or nurse or provider) adj1 (patient or client or family)).mp.
16. ((improv* or increas* or enhanc* or rais*) adj3 (knowledge or understanding or comprehension or aware*)).ti,ab,id.
17. ((health or patient* or client*) adj2 knowledge).mp.
18. (educat* or teach* or instruct* or train* or coach* or learn*).mp.
19. ((community or family or office or work* or school or faith or church) adj based).ti,ab,id.
20. (information* adj (service* or disseminat* or seek* or transfer* or campaign* or provid* or provision or aid or material* or sheet* or pack*)).mp.
21. ((patient or client or health or medical or written or print* or visual* or provid* or present* or vaccin* or immuni*) adj2 inform*).mp.
22. ((oral or text* or data or numerical or statistical or visual or graphic*) adj (format* or presentation* or display*)).mp.
23. (counsel* or advis* or advice* or social support or psychosocial or ((social or pastoral or spiritual) adj care)).mp.
24. ((support or peer) adj2 (intervention* or group* or program*)).mp.
25. ((social or community) adj2 network*).mp.
26. ((print* adj (material* or based or media)) or paper‐based or (paper adj1 pen*) or publication* or newsletter* or brochure* or booklet* or pamphlet* or leaflet* or flyer* or handout* or poster* or illustrat* or picture* or pictogram*).mp.
27. ((home* adj3 visit*) or interview* or session* or lecture* or meeting* or presentation*).mp.
28. (cultural* adj3 (service* or care or intervention* or appropriate* or sensitiv*)).mp.
29. (decision adj (making or support or aid*)).mp.
30. choice behavior/
31. (informed adj (consent or choice* or decision*)).mp.
32. ((patient or person or family or client) adj (cent*red or focus*ed or oriented)).mp.
33. or/8‐32
34. 7 and 33
35. random*.ti,ab,hw,id.
36. trial*.ti,ab,hw,id.
37. controlled stud*.ti,ab,hw,id.
38. placebo*.ti,ab,hw,id.
39. ((singl* or doubl* or trebl* or tripl*) and (blind* or mask*)).ti,ab,hw,id.
40. (cross over or crossover or factorial* or latin square).ti,ab,hw,id.
41. (assign* or allocat* or volunteer*).ti,ab,hw,id.
42. treatment effectiveness evaluation/
43. mental health program evaluation/
44. exp experimental design/
45. "2100".md.
46. or/35‐45
47. 34 and 46
48. limit 47 to yr="2012‐current"
49. 47 and (201207* or 201208* or 201209* or 201210* or 201211* or 201212* or 2013* or 2014* or 2015* or 2016* or 2017*).up.
50. 48 or 49

Appendix 10. Additional database search strategies

The International Clinical Trials Registry Platform (ICTRP) search strategy

Review authors searched for any planned or ongoing trials in the WHO International Clinical Trials Registry Platform (ICTRP) on 24 July 2017. Using the “Advanced search” function, the following was used in each field:
Title: vaccin* OR immuniz* OR immunis*
Intervention: educate OR educat* OR inform* OR promot* OR knowledge OR attitude OR teach* OR instruct* OR train* OR session* OR face to face OR communication OR communicat*
Recruitment status: ALL
Date: since 16/7/2012

ClinicalTrials.gov search strategy

Date searched: 24/7/2017

Other terms: (vaccine OR vaccination OR immunise OR immunize OR immunizing OR immunization) AND child AND (educate OR education OR teach OR train OR instruction OR inform OR promotion OR communication OR knowledge OR attitude OR session OR face to face)

Study type: Interventional Studies

Open Grey search strategy

Date searched: 24/7/2017

Search strategy: (vaccin*OR immunis*OR immuniz* OR immunotherap*OR inoculat*) AND (child*OR infant*OR parent*ORmother* or father* OR famil*) AND (educat* OR teach* OR train* OR instruct* OR inform* OR promot* OR persua* OR influenc* OR explain* OR advis* OR counsel* OR communicat* OR knowledge OR understand* OR attitude* OR session* OR campaign* OR messag* OR adverti*OR visit*OR “face to face”OR verbal*OR personal*OR individual* OR meeting*OR peer*OR “health* aide*”OR “health*‐worker*” OR “community‐based” OR “family‐based” OR “school‐based” OR “work*‐based” OR “church‐based” OR intervention*) AFTER 2010

Notes

New search for studies and content updated (conclusions changed)

Data and analyses

Comparison 1

Face‐to‐face education versus control or non‐face‐to‐face education (all)

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Characteristics of excluded studies [ordered by study ID]

Characteristics of ongoing studies [ordered by study ID]

Differences between protocol and review

Differences between original review and update

The following features or methods were changed from the original review (Kaufman 2013):

Outcomes: We changed the outcomes to reflect the development of research in this field. We added 'attitudes or beliefs' and moved 'intention to vaccinate' and 'adverse effects' to the primary outcomes.

Inclusion criteria: We excluded studies evaluating maternal support and educational interventions in which immunisation was not a primary component of the intervention content and where only immunisation coverage was measured. If immunisation knowledge was measured, we included the studies.

Time points: Changed relevant time point from first and last to just last.

Comparisons: We changed the comparisons to face‐to‐face vs usual care, and face‐to‐face A vs face‐to‐face B (removing group and individual distinction, as this was deemed not to be a meaningful distinction).

Search: In the update, we did not search Grey Literature Report because this database has been discontinued. We also did not search Global Health (CAB), or Global Health Library (WHO), as we determined they were low yield databases.

Selection of outcome when multiple outcomes within one category (attitudes or beliefs) were measured: We developed a process to select one outcome when multiple outcomes from a single category were measured and none were identified as the primary outcome. This plan involved comparing the outcome assessment tools to identify the most comparable measure across studies, as different choices of scales measured different aspects of attitudes.

Heterogeneity: We did not set an acceptable heterogeneity threshold for meta‐analysis.

Subgroup analyses: We added two post hoc formal subgroup analyses to investigate sources of heterogeneity among the studies reporting vaccination status. The two subgroups were based on intervention session length and number of vaccines received. These subgroups were identified by vaccination experts as relevant to practice and decision making. Session length has direct cost and time implications. Receipt of a single vaccine may be considerably less 'demanding' to achieve, as an outcome, than receipt of multiple or all required vaccines.

Contributions of authors

Review Update

Drafting updated review: JK

Searching for trials: JK

Selecting trials: JK, LW, RR

Data entry: JK, LW

Analysis: JK, RR, DH

Interpreting analysis: All

Commenting on and finalising updated review: All

Sources of support

Internal sources

• NHMRC, Australia.

  Infrastructure funding for Cochrane Collaboration activities (SH and RR)

External sources

• No sources of support supplied

Declarations of interest

JK received funding to undertake this review update from a La Trobe University, Building Health Communities Research Focus Area grant. Additional funding for JK was provided by the Centre for Health Communication and Participation. She is an editor with the CCC.

SH is the Coordinating Editor of the CCC and her contribution to this review was funded in part by a Cochrane Infrastructure Grant provided by the National Health and Medical Research Council (NHMRC).

RR is the Deputy Coordinating Editor of the CCC, and receives funding from a Cochrane Infrastructure Grant provided by the National Health and Medical Research Council (NHMRC).

DH is an editor with the CCC.

JL received funding from the Sydney Children's Hospital Network for work in developing a vaccination communication intervention.

No authors with editorial roles in the CCC were involved in the editorial or peer review process for this review.

References

References to studies included in this review

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References to ongoing studies

JPRN‐UMIN000012575 {published data only (unpublished sought but not used)}

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NCT02666872 {published and unpublished data}

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NCT02984007 {published and unpublished data}

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