Systematic review on measles and mass vaccination in the African continent

Measles is one of the most highly contagious infectious diseases worldwide, associated with substantial morbidity and mortality, especially among children under the age of five years. Although effective vaccines are available, sustaining high levels of population immunity remains difficult in many low- and middle-income countries (LMICs), particularly in regions with marginalised communities, conflict-affected areas, or where access to routine healthcare is limited. To overcome immunization gaps, many countries implement mass vaccination campaigns, either supplementary immunization activities (SIA) or outbreak response vaccination (ORV), to rapidly boost immunity and limit disease transmission. However the impact of these mass vaccination campaigns can vary. Amid ongoing measles outbreaks in the Africa continent, there is a growing need to better understand the impact and effectiveness of mass vaccination campaigns to inform the planning and implementation of preparedness and response strategies. A mixed methods systematic review will be conducted, adhering to the JBI approach, and reported adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, to address the following overarching systematic review question: • What is the effectiveness of mass measles vaccination campaigns on the incidence, morbidity and mortality of measles and the barriers to achieving high uptake of measles vaccination during mass campaigns in African countries? Studies which address the overarching systematic review question will also be used to address the following subsidiary questions: • What are the characteristics of mass vaccination campaigns in terms of organisation, delivery and assessments? • The cost-effectiveness related to the timing of ORI/SAI campaigns • To what extent have mass vaccination campaigns reached underserved populations (e.g., nomadic groups, urban slums, and conflict/affected areas, targeted populations and age groups)?