RTS,S Malaria Vaccine Efficacy Wanes over Time

Malaria vaccine was associated with a decrease in first and all episodes of malaria; efficacy fell to 16.8% at 4 years.

In a phase II trial of RTS,S/AS01E in children vaccinated at age 5 to 17 months in Kenya and Tanzania, efficacy against a first malaria episode was 46% at 15 months after the third vaccine dose. Investigators now provide 4-year efficacy data for one of the study sites (Kilifi, Kenya).

Participants in the extended follow-up study were limited to those randomized in the original study in Kilifi. The investigators calculated a malaria-exposure index based on the distance-weighted proportion of asymptomatic or symptomatic malaria cases within a 1-km radius of each child.

Three hundred twenty (71.6%) of the original participants completed 4 years of follow-up. Efficacy against first or only episodes of malaria was 29.9% in the intent-to-treat coho…

Reviewing Author

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine