VRC 314 is designed as an open-label evaluation of the safety, tolerability, immunogenicity and protective efficacy of PfSPZ Vaccine. This vaccine administered at 1.35 times 10(5) PfSPZ per injection by the IV route on a schedule of 5 vaccinations was previously shown to confer protection in all vaccinated subjects against CHMI performed shortly after last vaccination; however there was limited durability of protection in a small number of protected subjects who were rechallenged several months later. This study is designed to substantiate the initial results with the IV vaccination route for protection against CHMI. Based on the potential importance of dose and schedule in optimizing sustained immunity with this vaccine, an increase in PfSPZ IV dosage on schedules of 3 to 5 vaccinations will be evaluated for protection against CHMI conducted early (about 3 weeks) and late (about 24 weeks) after completion of vaccinations. To assess if a higher dose given by another route confers protection, one group will receive PfSPZ IM, with half of the amount administered in each arm on a schedule with 4 vaccination.