Protective efficacy of the RTS,S/AS02 Plasmodium falciparum malaria vaccine is not strain specific.
RTS,S/AS02 is a recombinant protein malaria vaccine that contains a large portion of the C-terminal of the circumsporozoite protein (CSP) sequence of the NF54 isolate of Plasmodium falciparum fused to the hepatitis B virus surface antigen. It has been shown to induce significant protection to challenge infection with a homologous parasite strain in American volunteers. In a recently completed trial in semi-immune Gambian adults, vaccine efficacy against natural infection was 34% (95% confidence interval = 8-53%, P = 0.014) during the malaria season following vaccination. Breakthrough P. falciparum parasites sampled from vaccinated subjects and from controls were genotyped at two polymorphic regions of the csp gene encoding T cell epitopes (csp-th2r and csp-th3r) to determine if the vaccine conferred a strain-specific effect. The overall distribution of csp allelic variants was similar in infections occurring in vaccine and control groups. Also, the mean number of genotypes per infection in the RTS,S/AS02 group was not reduced compared with the controls.
Alloueche
Ali
A
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom. ali.alloueche@lshtm.ac.uk
Milligan
Paul
P
Conway
David J
DJ
Pinder
Margaret
M
Bojang
Kalifa
K
Doherty
Tom
T
Tornieporth
Nadia
N
Cohen
Joe
J
Greenwood
Brian M
BM
D000293:Adolescent; D000328:Adult; D000818:Animals; D016054:DNA, Protozoan / Q000032:analysis; D000939:Epitopes / Q000235:genetics; D005787:Gene Frequency; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D006801:Humans; D017780:Malaria Vaccines; D016778:Malaria, Falciparum / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D016012:Poisson Distribution; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic
D016054:DNA, Protozoan; D000939:Epitopes; D005819:Genetic Markers; D006514:Hepatitis B Surface Antigens; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D014614:Vaccines, Synthetic; C041595:circumsporozoite protein, Protozoan