Sanaria PfSPZ Challenge With Pyrimethamine or Chloroquine Chemoprophylaxis Vaccination (PfSPZ-CVac Approach): A Randomized Double Blind Placebo Controlled Phase I/II Trial to Determine Safety and Protective Efficacy Against Natural Plasmodium Falcipa...

Background: Malaria remains a major global health problem. Malaria is spread by the bite of mosquitos. Africa is the region of the world where most people get malaria. Sanaria PfSPZ Challenge is a malaria vaccine. Researchers want to see if the vaccine combined with partner drugs can help protect against malaria. Objective: To test if injections with 3 monthly doses of Sanaria PfSPZ Challenge, combined with either pyrimethamine (PYR) or chloroquine as a partner drug, is safe, tolerable, and effective. Eligibility: Healthy people ages 18-50 years who live in Bancoumana, Mali, or nearby Design: Participants will be screened with the Malaria Comprehension Exam to check their understanding of the study. They will have a medical history. They will have a physical exam. They will have blood tests, urine tests, and heart tests. Participants will join either the pilot study or the main study. Participants will be assigned to groups. Depending on their group, they will get at least one injection of either a placebo or the vaccine. They may have up to 3 vaccines, 4 weeks apart. The injection will be into a vein with a needle. Participants will also take pyrimethamine or chloroquine by mouth. They will also take standard doses of antimalarial drugs by mouth. Participants will have blood tests throughout the study. Participants may develop a rash or injection site reaction. If this happens, photos of the site may be taken. Participants will be observed for infection for many days after the injections.