From Product Availability to Population Protection: Vaccine Deployment Readiness in Sierra Leone

Background: The 100 Days Mission has reorganised preparedness around vaccine development speed. Modelling suggests that meeting its target during the COVID-19 pandemic could have averted more than eight million deaths, conditional on equitable distribution. Distribution depends on a national pathway from authorisation through financing, cold chain, targeting, delivery, monitoring and community trust. The Mission measures speed at only one end of this system. Objective: To develop and apply a country-anchored framework for the deployment-readiness layer of preparedness. Methods: We conducted a comparative documentary analysis of three vaccine deployment events in Sierra Leone: COVID-19 vaccination in 2021, preventive Ebola vaccination in 2024 and mpox clade IIb vaccination in 2025. Sources included regulatory records, government and partner reports, national plans and aggregate programme records. We organised 11 established immunisation and emergency vaccination functions into a Deployment Readiness Chain. We traced constraints, handoffs, time to vaccination start and dated reach. Findings: COVID-19 vaccination began 45 days after European Medicines Agency authorisation. Full coverage among people aged 12 years or older reached 73.2% by December 2022 and a reported 86.7% by October 2023. More than 84% of doses were delivered through surge campaigns or periodic intensification of routine immunisation. Nationwide preventive Ebola vaccination reached 17,454 of the 20,621 targeted workers, or 84.6%, in three weeks. It began 1851 days after authorisation, although a global stockpile had been in operation since 2021. Mpox vaccination began 106 days after outbreak confirmation and reached 186,053 people by 14 December through capabilities built during earlier emergencies. Conclusions: For Ebola, the 1851-day interval spanned product authorisation, global preventive policy, financing and national activation. Product availability alone was not sufficient. Preparedness frameworks should evaluate deployment readiness alongside development speed. They should treat the global-to-national deployment pathway as one fundable category. Deployment readiness is built between emergencies, not during them.