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Review
. 2022 Nov 10;12(11):e058258.
doi: 10.1136/bmjopen-2021-058258.

Improving routine childhood immunisation outcomes in low-income and middle-income countries: an evidence gap map

Mark Engelbert  1 , Monica Jain  2 , Avantika Bagai  3 , Shradha S Parsekar  4
Affiliations
Review

Improving routine childhood immunisation outcomes in low-income and middle-income countries: an evidence gap map

Mark Engelbert et al. BMJ Open. .

Abstract

Objective: To support evidence-informed decision-making, we created an evidence gap map to characterise the evidence base on the effectiveness of interventions in improving routine childhood immunisation outcomes in low-income and middle-income countries (LMICs).

Methods: We developed an intervention-outcome matrix with 38 interventions and 43 outcomes. We searched academic databases and grey literature sources for relevant impact evaluations (IEs) and systematic reviews (SRs). Search results were screened on title/abstract. Those included on title/abstract were retrieved for full review. Studies meeting the eligibility criteria were included and data were extracted for each included study. All screening and data extraction was done by two independent reviewers. We analysed these data to identify trends in the geographic distribution of evidence, the concentration of evidence across intervention and outcome categories, and attention to vulnerable populations in the literature.

Results: We identified 309 studies, comprising 226 completed IEs, 58 completed SRs, 24 ongoing IEs and 1 ongoing SR. Evidence from IEs is heavily concentrated in a handful of countries in sub-Saharan Africa and South Asia. Among interventions, the most frequently evaluated are those related to education and material incentives for caregivers or health workers. There are gaps in the study of non-material incentives and outreach to vulnerable populations. Among outcomes, those related to vaccine coverage and health are well covered. However, evidence on intermediate outcomes related to health system capacity or barriers faced by caregivers is much more limited.

Conclusions: There is valuable evidence available to decision-makers for use in identifying and deploying effective strategies to increase routine immunisation in LMICs. However, additional research is needed to address gaps in the evidence base.

Keywords: community child health; health economics; health policy; paediatric infectious disease & immunisation; public health.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
Theory of change. Note: certain lines are dashed to increase the readability of the diagram; the different line styles do not indicate different types of relationships.
Figure 2
Figure 2
Broad categories in the intervention–outcome matrix.
Figure 3
Figure 3
Preferred Reporting Items for Systematic Reviews and Meta-Analyses diagram of search and screening process. IE, impact evaluation; SR, systematic review.
Figure 4
Figure 4
Impact evaluations by country diphtheria, tetanus and pertussis (DPT)3 coverage rate. Map based on longitude (generated) and latitude (generated). Colour shows sum of DPT3 coverage rate. The marks are labelled by sum of impact evaluations. Details are shown for country.
Figure 5
Figure 5
Impact evaluations and systematic reviews (SRs) by specific intervention category. HW, health worker; SES, socioeconomic status; HMIS, health management information system.
Figure 6
Figure 6
Impact evaluations and systematic reviews (SRs) by broad outcome category.
Figure 7
Figure 7
Impact evaluations and systematic reviews (SRs) by specific outcomes related to behavioural, social and practical barriers faced by caregivers and communities.
Figure 8
Figure 8
Impact evaluations and systematic reviews (SRs) by specific outcomes related to delivery of vaccination services. HW, health worker; CHW, community health worker.
Figure 9
Figure 9
Impact evaluations and systematic reviews (SRs) by specific coverage and health outcomes. DPT, diphtheria, tetanus and pertussis vaccine; IPV, inactivated polio vaccine; BCG, Bacillus Calmette-Guérin vaccine; OPV, oral polio vaccine.
Figure 10
Figure 10
Attention to equity in included studies. SES, socioeconomic status.
See this image and copyright information in PMC

References

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