Implementation trial Guinea

The WHO recommends administering at least one booster dose of the malaria vaccine to children ~1 year after their initial vaccination series (priming doses). This advice is based largely on the design of the clinical trials of the RTS,S/AS01E vaccine that led to its registration, which were conducted mainly in settings of perennial malaria transmission. However, in areas with strong seasonal malaria transmission, it might be more effective to administer the boosters immediately prior to the following malaria transmission season, regardless of the precise age of the child at that time or of the interval since they received their 3^rd priming dose. Such seasonal boosting was previously shown in neighbouring country Mali to have an additive effect in reducing malaria incidence in children under 5 years of age, on top of the implementation of seasonal malaria chemoprevention (SMC) with sulphadoxine-pyrimethamine plus amodiaquine (SP+AQ), during the peak period of malaria risk. However, debate remains about the best approach to deliver the booster doses, as these two strategies have never been assessed side-by-side.  The main objective of this study in Guinea is thus to investigate whether season-based boosting (immediately prior to the malaria transmission season, intervention area) with RTS,S/AS01E achieves better coverage and a greater reduction in malaria incidence than age-based timing of booster doses (fixed timepoint after the last vaccination, control area). This is  a pragmatic implementation study, involving two cohorts of children. Two areas that have comparable malaria epidemiology, social structure, coverage of EPI vaccines, and access to treatment have been identified in Mamou, one of the districts in Guinea selected for the initial roll out of RTS,S/AS01E vaccine by the Guinea Ministry of Health. This project will provide important information on the optimum delivery of malaria vaccine booster doses in settings of seasonal malaria transmission, which could save many lives.