Malaria vaccine trial in African children - preliminary results

January 01, 0001

Malaria vaccine trial in African children - preliminary results

An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries by investigators from multiple countries. From March 2009 through January 2011, they enrolled 15,460 children in two age categories — 6 to 12 weeks of age and 5 to 17 months of age — for vaccination with either RTS,S/AS01 or a non-malaria comparator vaccine. The primary end point of the analysis was vaccine efficacy against clinical malaria during the 12 months after vaccination in the first 6000 children 5 to 17 months of age at enrollment who received all three doses of vaccine according to protocol. After 250 children had an episode of severe malaria, they evaluated vaccine efficacy against severe malaria in both age categories.

They found: "In the 14 months after the first dose of vaccine, the incidence of first episodes of clinical malaria in the first 6000 children in the older age category was 0.32 episodes per person-year in the RTS,S/AS01 group and 0.55 episodes per person-year in the control group, for an efficacy of 50.4% in the intention-to-treat population and 55.8% in the per-protocol population. Vaccine efficacy against severe malaria was 45.1% in the intention- to-treat population and 47.3% in the per-protocol population. Vaccine efficacy against severe malaria in the combined age categories was 34.8% in the per- protocol population during an average follow-up of 11 months. Serious adverse events occurred with a similar frequency in the two study groups. Among children in the older age category, the rate of generalized convulsive seizures after RTS,S/AS01 vaccination was 1.04 per 1000 doses."

The authors concluded: "The RTS,S/AS01 vaccine provided protection against both clinical and severe malaria in African children."

These results are promising.

For the full abstract, click here.

N Engl J Med online 18 October 2011 © 2011 to the Massachusetts Medical Society
First Results of Phase 3 Trial of RTS,S/AS01 Malaria Vaccine in African Children. The RTS,S Clinical Trials Partnership. Correspondence to Ms. Kelsey Mertes: kmertes@path.org

Category: B. Blood, Immune Mechanisms. Keywords: malaria, children, Africa, vaccine, randomized controlled trial, journal watch.
Synopsis edited by Dr Linda French, Toledo, Ohio. Posted on Global Family Doctor 15 November 2011

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