A PILOT SAFETY AND IMMUNOGENICITY STUDY OF THE MALARIA VACCINE SPF66 IN GAMBIAN INFANTS

A pilot safety and immunogenicity trial of the malar ia vaccine SPf66 has been undertaken in 150 Gambian infants. No significant systemic si de effects were recorded but modest local reactions were seen after th e administration of a third 1.0 mg dose. SPf66 produced in Colombia wa s more immunogenic than SPf66 produced in the USA and a 1.0 mg dose of each vaccine gave higher antibody levels than a 0.5 mg dose. However, antibody levels fell rapidly after administration of the third dose o f vaccine and showed little change over the following malaria transmis sion season. The incidence of clinical malaria was higher among childr en who received SPf66 than among children who received inactivated pol io vaccine, the effect being most marked among children who received 1 .0 mg Colombian SPf66. As the trial was not designed to measure the ef fect of SPf66 on morbidity from malaria, the significance of this find ing is uncertain.