Malaria vaccine candidate demonstrates efficacy over 3-4 years of follow-up

Final results from a large-scale Phase III trial of the RTS,S malaria vaccine candidate, including the impact of a booster dose, published today in The Lancet, show that the vaccine candidate helped protect children and infants from clinical malaria for at least three years after first vaccination.

11 research centres in seven African countries2 conducted the efficacy and safety trial, in partnership with UK pharma major GlaxoSmithKline (LSE: GSK) and the PATH Malaria Vaccine Initiative (MVI), with grant funding from the Bill & Melinda Gates Foundation to MVI. The trial, started in March 2009 and concluded in January 2014, enrolled 15,459 participants, in two age categories: children (aged 5-17 months at first vaccination) and infants (aged 6-12 weeks at first vaccination).

The latest results demonstrated that vaccination with RTS,S, followed by a booster dose of RTS,S administered 18 months after the primary schedule, reduced the number of cases of clinical malaria in children (aged 5-17 months at first vaccination) by 36% to the end of the study (over an average follow-up of 48 months across trial sites) and in infants (aged 6-12 weeks at first vaccination) by 26% to the end of the study (over an average follow-up of 38 months across trial sites). Efficacy decreased over time in both age groups. Without the booster dose, the 3-dose primary schedule reduced clinical malaria cases by 28% in children and 18% in infants to the study end. The efficacy of RTS,S was evaluated in the context of existing malaria control measures, such as insecticide treated bed nets, which were used by approximately 80% of the children and infants in the trial.