title: Four year immunogenicity of the RTS,S/AS02(A) malaria vaccine in Mozambican children during a phase IIb trial.
abstract: 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.
authors: Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique. pedro.aide@manhica.net
authors: Pedro
authors: P
authors: Aide
authors: Carlota
authors: C
authors: Dobaño
authors: Jahit
authors: J
authors: Sacarlal
authors: John J
authors: JJ
authors: Aponte
authors: Inácio
authors: I
authors: Mandomando
authors: Caterina
authors: C
authors: Guinovart
authors: Quique
authors: Q
authors: Bassat
authors: Montse
authors: M
authors: Renom
authors: Laura
authors: L
authors: Puyol
authors: Eusebio
authors: E
authors: Macete
authors: Esperanza
authors: E
authors: Herreros
authors: Amanda
authors: A
authors: Leach
authors: Marie-Claude
authors: MC
authors: Dubois
authors: Marie-Ange
authors: MA
authors: Demoitie
authors: Marc
authors: M
authors: Lievens
authors: Johan
authors: J
authors: Vekemans
authors: Christian
authors: C
authors: Loucq
authors: W Ripley
authors: WR
authors: Ballou
authors: Joe
authors: J
authors: Cohen
authors: Pedro L
authors: PL
authors: Alonso
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood; D002675:Child, Preschool; D004311:Double-Blind Method; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D006801:Humans; D007223:Infant; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology / Q000517:prevention & control*; D009073:Mozambique; D010963:Plasmodium falciparum / Q000276:immunology; D015800:Protozoan Proteins / Q000276:immunology; D016896:Treatment Outcome
chemical_list: D000913:Antibodies, Protozoan; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C493155:RTS,S-AS02A vaccine; C041595:circumsporozoite protein, Protozoan