title: Vaccination with SPf66, a chemically synthesised vaccine, against Plasmodium falciparum malaria in Colombia.
abstract: Preclinical and clinical studies have established the safety and immunogenicity of the chemically synthesised SPf66 malaria vaccine. The present study is a phase III randomised, double-blind, placebo-controlled, efficacy trial completed in La Tola, Colombia. 1548 volunteers over one year of age received three doses of either the vaccine (n = 738) or placebo (n = 810). Active and passive case detection methods were used to document clinical episodes of malaria among the study population. The follow-up period began one month after the third dose and lasted for one year. 168 and 297 episodes of Plasmodium falciparum malaria were documented in the SPf66 group and the placebo group, respectively; this corresponds to a crude protective efficacy of 38.8%. Incidence rates for first or only P falciparum malarial episodes were 22.3% per annum among the vaccinee group and 33.5% among the placebo group (RR = 1.5; 95% Cl 1.23, 1.84). Therefore, the protective efficacy of SPf66 against first or only episodes was 33.6% (95% Cl 18.8, 45.7), being highest in children aged 1-4 years (77%) and adults older than 45 years (67%). The estimated protective efficacy against second episodes was 50.5% (95% Cl 12.9-71.9). Our study shows that the chemically synthesised SPf66 malaria vaccine is safe, immunogenic, and protective against P falciparum malaria in semi-immune populations subject to natural challenge.
authors.affiliation: Instituto de Inmunología, Hospital San Juan de Dios, Universidad Nacional de Colombia, Bogota.
authors.forename: M V
authors.initials: MV
authors.lastname: Valero
authors.forename: L R
authors.initials: LR
authors.lastname: Amador
authors.forename: C
authors.initials: C
authors.lastname: Galindo
authors.forename: J
authors.initials: J
authors.lastname: Figueroa
authors.forename: M S
authors.initials: MS
authors.lastname: Bello
authors.forename: L A
authors.initials: LA
authors.lastname: Murillo
authors.forename: A L
authors.initials: AL
authors.lastname: Mora
authors.forename: G
authors.initials: G
authors.lastname: Patarroyo
authors.forename: C L
authors.initials: CL
authors.lastname: Rocha
authors.forename: M
authors.initials: M
authors.lastname: Rojas
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003105:Colombia; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D011994:Recombinant Proteins; D016896:Treatment Outcome
chemical_list: D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D011994:Recombinant Proteins; C066269:SPf66 protein, Plasmodium