International Initiative for Impact Evaluation, London, UK
International Initiative for Impact Evaluation, New Delhi, India.
BMJ Open. 2022 Nov 10;12(11):e058258. doi: 10.1136/bmjopen-2021-058258.
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).
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.
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.
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.
为支持循证决策，我们制作了证据差距图，以描述在改善低收入和中等收入国家（LMICs）常规儿童免疫接种结果方面干预措施的有效性的证据基础。
我们制定了一个干预措施-结果矩阵，其中包含 38 种干预措施和 43 种结果。我们在学术数据库和灰色文献来源中搜索了相关的影响评估（IEs）和系统评价（SRs）。搜索结果经过标题/摘要筛选。那些在标题/摘要中包含的内容被检索进行全文审查。符合入选标准的研究被纳入，并对每个入选研究进行数据提取。所有筛选和数据提取均由两名独立评审员进行。我们对这些数据进行分析，以确定证据在地理分布上的趋势、干预措施和结果类别在证据集中的集中程度，以及文献中对弱势群体的关注。
我们确定了 309 项研究，其中包括 226 项已完成的 IE、58 项已完成的 SR、24 项正在进行的 IE 和 1 项正在进行的 SR。IE 提供的证据主要集中在撒哈拉以南非洲和南亚的少数几个国家。在干预措施中，评估最多的是与照顾者或卫生工作者的教育和物质激励相关的措施。在非物质激励和接触弱势群体方面的研究存在差距。在结果方面，与疫苗覆盖率和健康相关的结果得到了很好的涵盖。然而，关于与卫生系统能力或照顾者面临的障碍相关的中间结果的证据要少得多。
决策者可以利用现有的有价值的证据来确定和部署有效的策略，以增加 LMICs 的常规免疫接种。然而，需要进一步研究来解决证据基础中的差距。
