MAVACHE is a sequential dose and schedule optimization trial of intravenous immunization with PfSPZ Vaccine in 18 to 54 malaria-naïve, healthy adult volunteers receiving 9x10^5, 1.35x10^6, or 2.7x10^6 PfSPZ per dose and a total dose between 2.7x10^6 and 8.1x10^6 PfSPZ followed by CHMI with 3,200 fully infectious PfSPZ (PfSPZ Challenge).