Four year immunogenicity of the RTS,S/AS02(A) malaria vaccine in Mozambican children during a phase IIb trial

Vaccine. 2011 Aug 11;29(35):6059-67. doi: 10.1016/j.vaccine.2011.03.041. Epub 2011 Apr 7.


Previous studies with the malaria vaccine RTS,S/AS02(A) in young children in a malaria endemic area of Mozambique have shown it to have a promising safety profile and to reduce the risk of Plasmodium falciparum infection and disease. In this study, we assessed the antibody responses to the P. falciparum and hepatitis B components of the RTS,S/AS02(A) vaccine over a 45 months surveillance period in a large phase IIb trial which included 2022 children aged 1-4 years at recruitment. The RTS,S/AS02(A) vaccine induced high anti-circumsporozoite antibody levels with at least 96% of children remaining seropositive during the entire follow-up period. IgG titers decayed over the first 6 months of follow-up to about 25% of the initial level, but still remained 30-fold higher until month 45 compared to controls. Children with higher levels of naturally acquired immunity at baseline, assessed by blood stage indirect fluorescent antibody test, had slightly higher anti-circumsporozoite levels, after adjusting for the effect of age. The RTS,S/AS02(A) vaccine also induced high levels of anti-hepatitis B surface antigen antibodies (seroprotection >97%). RTS,S/AS02(A) vaccine is immunogenic and induces long-lasting anti-circumsporozoite antibodies, persisting at least 42 months after immunization. These antibodies may play a role in protection against malaria.

Trial registration: NCT00197041 NCT00323622.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Protozoan / blood
  • Child, Preschool
  • Double-Blind Method
  • Hepatitis B Antibodies / blood
  • Hepatitis B Surface Antigens / immunology
  • Humans
  • Infant
  • Malaria Vaccines / administration & dosage
  • Malaria Vaccines / immunology*
  • Malaria, Falciparum / immunology
  • Malaria, Falciparum / prevention & control*
  • Mozambique
  • Plasmodium falciparum / immunology
  • Protozoan Proteins / immunology
  • Treatment Outcome


  • Antibodies, Protozoan
  • Hepatitis B Antibodies
  • Hepatitis B Surface Antigens
  • Malaria Vaccines
  • Protozoan Proteins
  • RTS,S-AS02A vaccine
  • circumsporozoite protein, Protozoan

Associated data