Use of community engagement interventions to improve child immunisation in low-income and middle-income countries: a systematic review and meta-analysis

OBJECTIVE: To support evidence informed decision-making, we systematically examine the effectiveness and cost-effectiveness of community engagement interventions on routine childhood immunisation outcomes in low-income and middle-income countries (LMICs) and identify contextual, design and implementation features associated with effectiveness. DESIGN: Mixed-methods systematic review and meta-analysis. DATA SOURCES: 21 databases of academic and grey literature and 12 additional websites were searched in May 2019 and May 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We included experimental and quasi-experimental impact evaluations of community engagement interventions considering outcomes related to routine child immunisation in LMICs. No language, publication type, or date restrictions were imposed. DATA EXTRACTION AND SYNTHESIS: Two independent researchers extracted summary data from published reports and appraised quantitative risk of bias using adapted Cochrane tools. Random effects meta-analysis was used to examine effects on the primary outcome, full immunisation coverage. RESULTS: Our search identified over 43 000 studies and 61 were eligible for analysis. The average pooled effect of community engagement interventions on full immunisation coverage was standardised mean difference 0.14 (95% CI 0.06 to 0.23, I(2)=94.46). The most common source of risk to the quality of evidence (risk of bias) was outcome reporting bias: most studies used caregiver-reported measures of vaccinations received by a child in the absence or incompleteness of immunisation cards. Reasons consistently cited for intervention success include appropriate intervention design, including building in community engagement features; addressing common contextual barriers of immunisation and leveraging facilitators; and accounting for existing implementation constraints. The median intervention cost per treated child per vaccine dose (excluding the cost of vaccines) to increase absolute immunisation coverage by one percent was US$3.68. CONCLUSION: Community engagement interventions are successful in improving outcomes related to routine child immunisation. The findings are robust to exclusion of studies assessed as high risk of bias.