@article{ba0c769e505646a39aba721eff1fbf49,
title = "Prevalence and dynamics of missed opportunities for vaccination among children in Africa: applying systems thinking in a systematic review and meta-analysis of observational studies",
abstract = "Objective: To estimate the prevalence of missed opportunities for vaccination (MOV) among children aged 0–23 months attending health-care facilities in Africa and explore the factors responsible for MOV using systems thinking. Research design and methods: We conducted a systematic review and meta-analysis of studies reporting the proportion MOVs. Five electronic databases were searched. A random effects model was fitted to obtain pooled estimates of MOV and a causal loop diagram (CLD) was constructed to explore the dynamics of the causes of MOV. MOV was defined as any contact with health services in Africa, by an unvaccinated or under-vaccinated child, aged 0–23 months, who is eligible for vaccination and free of any contraindication, which does not result in vaccination. Results: Four hundred and twenty-one publications were found, of which 20 studies from 14 countries were included. The pooled prevalence of MOV was estimated to be 27.26% (95%CI: 18.80–36.62). A CLD with seven reinforcing and two balancing loops were constructed. Conclusion: Our findings suggest that about one in every four children under the age of two years who visited health facilities in 14 African countries missed the vaccination they were eligible to receive. To enable continent-wide estimates, more MOV assessments are required.",
keywords = "Africa, Immunization, causal loop diagram, children, missed opportunities for vaccination, systematic review, systems thinking, vaccines",
author = "Adamu, {Abdu A.} and Sarki, {Ahmed M.} and Uthman, {Olalekan A.} and Wiyeh, {Alison B.} and Gadanya, {Muktar A.} and Wiysonge, {Charles S.}",
note = "Funding Information: A. Adamu and C. Wiysonge are supported by the South African Medical Research Council and the National Research Foundation of South Africa. O Uthman receives support from the National Institute of Health{\textquoteright}s Official Development Assistance (ODA). A Wiyeh is supported by the South African Medical Research Council. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. Funding Information: The research reported in this publication was supported by the South African Medical Research Council with funds received from the National Research Foundation of South Africa through its competitive programme for rated researchers. This work is based on research supported wholly/in part by the National Research Foundation of South Africa (Grant Number: 106035). Funding Information: The research reported in this publication was supported by the South African Medical Research Council with funds received from the National Research Foundation of South Africa through its competitive programme for rated researchers. This work is based on research supported wholly/in part by the National Research Foundation of South Africa (Grant Number: 106035). We are grateful to the information specialist and librarians that supported this review with technical assistance. Joy Oliver of Cochrane South Africa, South African Research Council, Tygerberg, assisted with the development of the search strategy that was used in this review. Ingrid van der Westhuizen, Tracey Louw and Pamela Nyokwana, of the Medicine and Health Science Library of Stellenbosch University, South Africa assisted with retrieving published manuscript through inter library loan. Publisher Copyright: {\textcopyright} 2019, {\textcopyright} 2019 Informa UK Limited, trading as Taylor & Francis Group.",
year = "2019",
month = may,
day = "4",
doi = "10.1080/14760584.2019.1588728",
language = "English",
volume = "18",
pages = "547--558",
journal = "Expert Review of Vaccines",
issn = "1476-0584",
publisher = "Taylor and Francis Ltd.",
number = "5",
}
