Article

SPf66 malaria vaccine is safe and immunogenic in malaria naive adults in Thailand.

Vaccine Trial Center, Mahidol University, Thailand.
Acta Tropica (impact factor: 2.72). 10/1997; 67(3):215-27. pp.215-27
Source: PubMed

ABSTRACT In preparation for an efficacy trial of malaria vaccine SPf66 in Thailand, a series of overlapping Phase I trials were conducted of US-manufactured SPf66. Here, two clinical lots were evaluated for safety and immunogenicity in a combined open-label trial. Eleven healthy, malaria naive, 18-44 year-old Thai men and women received three doses by subcutaneous injection in alternate arms at 0, 1 and 6 months. Safety was assessed by monitoring local and systemic reactogenicity and laboratory parameters. Common side effects were mild erythema, induration and tenderness at the site of injection which resolved within 24-48 h. At third immunization, two volunteers developed acute bilateral reactions with induration, erythema and pruritus limited to the sites of the second and third immunizations. Eight of 11 volunteers sero-converted by ELISA, six of whom would be classified as high responders by Colombian standards. Eight of 11 volunteers developed a lymphoproliferative response to the SPf66 antigen. Side effects were more common and antibody and lymphoproliferative responses greatest, among the four female volunteers. This initial study of SPf66 malaria vaccine in Asia constitutes an essential link between the initial Phase I study in the US and subsequent field studies in a semi-immune population in a malaria endemic area of Thailand. This study further establishes comparability of US-manufactured SPf66 with that of Colombian provenance and substantiates the validity of the subsequent negative efficacy results of SPf66 in a field trial in Thailand.

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Keywords

11 volunteers
 
11 volunteers sero-converted
 
18-44 year-old Thai men
 
6 months
 
acute bilateral reactions
 
Colombian standards
 
combined open-label trial
 
Common side effects
 
four female volunteers
 
initial study
 
lymphoproliferative responses greatest
 
malaria endemic area
 
malaria vaccine SPf66
 
pruritus limited
 
SPf66 malaria vaccine
 
subsequent field studies
 
subsequent negative efficacy results
 
systemic reactogenicity
 
US-manufactured SPf66
 
women