Assessing the resilience of child immunisation programmes using geospatial modelling and interrupted time series analysis in Ethiopia and Kenya amidst the COVID-19 pandemic: tracking coverage and identifying key challenges.

Introduction: The COVID-19 pandemic disrupted healthcare provision and access in sub-Saharan Africa. Lockdowns and travel restrictions, coupled with fear of contracting the virus, disrupted services, especially for women's and children's health, derailing progress on sustainable development goals. This paper examines the impact of the COVID-19 pandemic on routine child immunisation coverage in Ethiopia and Kenya at both national and subnational levels. Methods: Health management information systems data were used to estimate changes in child immunisation. Mean differences in coverage between the pre-COVID-19 and during COVID-19 were tested at a 5% significance level. Geospatial maps for coverage and differences between the two periods were created using aggregated proportions. Interrupted time series analyses provided counterfactual coverage assessments, assuming no COVID-19 impact. Results: At the national level, minor short-term disruptions in coverage were observed following pandemic peaks in Kenya and Ethiopia, which were considered statistically insignificant. In Ethiopia, a subnational assessment reveals that full vaccination coverage remained relatively stable, with significant changes observed in the southeast regions of Somali and Dire Dawa. Specific vaccines such as BCG, diphtheria, pertussis and tetanus 3 and polio (OPV3) showed considerable coverage changes in most regions except Oromia, Gambela and Sidama. Measles vaccine coverage experienced major changes across almost all regions of Ethiopia. In Kenya, full vaccination coverage experienced significant changes in eight counties, including Kisii, Turkana and Marsabit, with most Kenyan counties experiencing significant changes in measles vaccine coverage. Conclusion: In conclusion, while routine immunisation services were mostly sustained with short-term disruptions at the national level in Ethiopia and Kenya, subnational levels experienced notable changes. The resilience of child immunisation was due to the implementation of community-based healthcare, mobile vaccinations and collaboration and partnerships for mass vaccination campaigns. The temporary disruptions were likely due to pandemic-related fears and supply chain restrictions.