Malaria caused by Plasmodium falciparum continues to be a global problem with devastating consequences. New interventions are needed to combat malaria, and progress is being made in development of vaccines: a subunit vaccine called RTSS confers partial protection against clinical malaria in children and is nearing licensure; a whole organism product called PfSPZ Vaccine can confer sterile protection against infection, and is now undergoing field trials. NIAID is involved in field trials of PfSPZ Vaccine and other vaccines, and a key question in vaccine trial design has been whether concurrent parasitemia will impair vaccine responses. The primary hypothesis in this study is that T cell suppression and regulation will decrease following antimalarial treatment that clears blood stage parasites for an extended period of time.