White M, et al. - Across the African meningitis belt, around 280 million individuals aged 1–29 years have been immunized using a meningococcal group A conjugate vaccine, PsA-TT (also known as MenAfriVac), that was developed with the support of the Meningitis Vaccine Project. In this work, the kinetics of vaccine-induced antibody response was determined and the possible implications for the duration of protection were assessed via analyzing data from two longitudinal studies done in The Gambia, Mali, and Senegal of antibody responses in 193 children aged 12–23 months and 604 participants aged 2–29 years following MenAfriVac vaccination. Findings suggest the persistence of population-level immunity induced by routine vaccination with the Expanded Programme on Immunization at levels sufficient to confer more than 50% protection over a 20-year time period. Undertaking mass campaigns or delaying the age of vaccination through the Expanded Programme on Immunization may further increase the population-level immunity. However, further investigation is required to assess the benefits of such a strategy against the risks of leaving young children unvaccinated for longer.