An additional Phase 3 study, conducted between 2017 and 2022 in Burkina Faso and Mali, compared the efficacy of RTS,S to that of seasonal malaria chemoprevention (SMC), which is the standard treatment for children in areas with highly seasonal malaria transmission.4

Results from the first three years of the study showed that RTS,S is comparable to SMC in preventing malaria, and that combining the two interventions has significantly greater impact than the use of each intervention alone. Use of the two interventions together resulted in an approximately 70% further reduction in malaria deaths and hospitalizations, and a 60% reduction in uncomplicated malaria over use of SMC alone.

Drawing on this evidence, WHO recommendation for broad use of RTS,S also notes that countries may consider providing the vaccine in areas with highly seasonal malaria or areas of perennial malaria transmission with seasonal peaks. 

[1] Chandramohan D, Zongo I, Sagara I, et al. Seasonal Malaria Vaccination with or without Seasonal Malaria Chemoprevention. New England Journal of Medicine. 2021; 385:1005-1017. doi: 10.1056/NEJMoa202330.