Safety and immunogenicity of PfSPZ Vaccine in Equatorial Guinea (EGSPZV1)

This is a single center, randomized, placebo-controlled, double-blind trial to assess the safety and immunogenicity of PfSPZ Vaccine administered by direct venous inoculation (DVI).The study to be conducted in Baney District, Bioko Island, Equatorial Guinea (EG), will be to establish whether three doses of the higher regimen - three doses of 2.7x10^5 PfSPZ of the PfSPZ Vaccine administered at 8 week intervals - is as well-tolerated and efficacious in malaria exposed African adults as the five dose regimens. Specifically, the trial will address the following objectives: is the three dose regimen: 1. Safe and well tolerated in Equatoguinean (EG) adults. 2. As immunogenic in EG adults as is the five-dose regimen of 1.35x10^5 PfSPZ in Tanzanian and U.S. adults or as three-, four- and five-dose regimens of 2.7x10^5 PfSPZ being tested in Tanzanian, Malian and U.S. adults. In addition, as an exploratory objective, the volunteers in the EG trial will be followed longitudinally to measure the incidence of malaria during the initial six months following immunization, providing a preliminary assessment of efficacy.