The details of the U.S. adult Phase 1 trial [16] and the Phase 2 trial in Malian children [25] have been supplied elsewhere (NCT00344539 and NCT00341250). In brief, adults 18-45 years of age were enrolled in the U.S. trial and they were immunized on Days 0, 28 and 56 with 20 or 80 mg of AMA1-C1 (a mixture of the recombinant AMA1-FVO and AMA1-3D7 proteins) formulated on AlhydrogelH and mixed with CPG 7909. Plasma samples from individuals with high levels of anti-AMA1 antibody (as determined by ELISA) on Day 70 were collected 3 months after the final vaccination. For the Mali trial, Malian children 2-3 years old were enrolled and immunized on Days 0 and 28 either with 80 mg of AMA1-C1 on AlhydrogelH or a comparator vaccine (HiberixH). Blood samples were collected on Days 0 and 42. Both trials were conducted under Investigational New Drug Applications reviewed by the U.S. Food and Drug Administration. The U.S. Phase 1 trial was reviewed and approved by the Institutional Review Boards (IRB) of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH) and by the University of Rochester Research Subjects Review Board. Written informed consent was obtained from all volunteers. The Mali Phase 2 trial was reviewed and approved by the IRB of NIAID at NIH and by the Ethics Committee of the Faculty of Medicine, Pharmacy and Dentistry, University of Bamako. Community consent was obtained at a meeting with village leaders, heads of families, and other community members prior to the start of the Phase 2 study. Individual informed consent was then obtained after oral translation of the consent form into the local language. Understanding of the contents of the consent was confirmed by means of a multiple choice questionnaire. Parents or guardians unable to read placed an imprint of his/her finger in place of a signature; an independent witness also signed all consent forms.