Prevalence of zero-dose vaccination among children aged 12–59 months in conflict-affected settings in Africa: a systematic review and meta-analysis

Background Although some individual studies have examined the prevalence of zero-dose vaccination, the pooled prevalence of zero-dose vaccination among children in conflict-affected African settings has not yet been estimated. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence of zero-dose vaccination among children aged 12–59 months in conflict-affected African settings. Methods A comprehensive systematic search was performed across six major databases: PubMed, Cochrane Library, Scopus, Science Direct, African Journals Online (AJOL), and Google Scholar using Medical Subject Heading (MeSH) terms alongside relevant keywords. Before the screening, all retrieved records were imported into EndNote version 25, and duplicates were removed. Using Covidence software, two reviewers independently carried out data screening and extraction. The Joanna Briggs Institute (JBI) critical appraisal checklist was used to evaluate the quality of the included studies. The extracted data were exported to STATA version 17 for statistical analysis. The pooled prevalence of zero-dose vaccination was estimated using random-effects model and presented using forest plots. The I² statistic was used to assess study heterogeneity, while funnel plot and Egger’s and Begg’s tests were used to evaluate publication bias. Results Of the 1,087 studies identified, 12 were included in the final analysis, comprising 30,423 children, with sample sizes ranging from 355 to 9,651. The reported prevalence of zero-dose vacccination ranged from 10.7% in Ethiopia to 60.2% in Somalia. In the country-level subgroup analysis, Nigeria had the lowest prevalence (22.0%; 95% CI: 18.0–26.9%), while Somalia had the highest prevalence (58.0%; 95% CI: 56.0–60.0%). The overall pooled prevalence of zero-dose vaccination in conflict-affected African settings was 36.0% (95% CI: 27.0–45.0%). Conclusions This study revealed that one in three children in conflict-affected African settings were zero-dose children. This striking gap highlights an urgent imperative for targeted, context-specific interventions to enhance routine vaccination services. Policymakers and partners should prioritize rebuilding immunization infrastructure and ensuring the availability and accessibility of vaccination services through mobilizing and allocating resources in conflict-affected settings. Furthermore, identifying and reaching zero-dose children through catch-up vaccination campaigns is essential to ensure that no child is left behind unvaccinated in conflict settings.