To bolster the data and information for decisions on future use of RTS,S, a set of observational studies was incorporated into the evaluation component of the malaria vaccine pilots in Ghana, Kenya, and Malawi.

The case control studies will provide additional estimates of RTS,S effectiveness and information about safety in children. The studies will also ascertain the added health benefit of the fourth dose, compared to a three-dose regimen, when implemented through the routine childhood immunizatio program. The case control studies began in 2021 and are expected to end in 2023.