Reaching zero-dose children in conflict-affected and fragile settings in the WHO African Region: a scoping review of strategies and evidence gaps.

Objectives: To map interventions and strategies targeting zero-dose children in fragile and conflict-affected settings across the WHO African Region and identify key evidence gaps to inform future research and programming. Design: Scoping review conducted in accordance with Joanna Briggs Institute methodology and reported using Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines. Data sources: PubMed (MEDLINE), CINAHL, Scopus and Web of Science, supplemented by grey literature searches of the WHO, UNICEF evaluation database and Gavi Alliance resource library (searched November 2025). Reference lists of relevant reviews were manually screened for additional studies. Eligibility criteria: Studies describing interventions or strategies to improve vaccination coverage or equity among zero-dose, unvaccinated or unimmunised children under 5 years in WHO African Region countries classified as fragile and conflict-affected per the World Bank Group's harmonised list. Editorials and commentaries lacking empirical or programmatic data were excluded. Data extraction and synthesis: Data were extracted using a pre-tested form capturing study characteristics, conflict setting, delivery models, target populations, barriers and implementation strategies. Findings were synthesised using deductive thematic analysis guided by the Identify-Reach-Monitor-Measure-Advocate framework. Formal risk of bias assessment was not conducted, consistent with scoping review methodology. Results: Five studies (n=5) published between 2018 and 2025 met inclusion criteria, covering Nigeria, Cameroon, the Central African Republic, South Sudan and Ethiopia. Interventions relied on non-immunisation platforms, integrated service delivery, security-supported or negotiated access and technology-enabled logistics. Evidence was more concentrated on identifying and reaching zero-dose children than on monitoring, measurement or advocacy. Key gaps included limited economic evidence, weak gender-barrier assessment and denominator uncertainty. Conclusions: Zero-dose children in conflict-affected and fragile settings can be reached through flexible, locally adapted strategies. However, the evidence base remains small and largely descriptive. Progress towards Immunization Agenda 2030 requires greater investment in context-appropriate implementation research and more systematic programme documentation.