A Phase 1 Trial of PfSPZ Vaccine in Healthy Adults to Determine Safety, Tolerability and Efficacy Against Heterologous CHMI

1. Randomized, phase 1, double-blind, placebo-controlled clinical trial enrolling healthy adult participants 18-50-years-old living in the US. 2. The trial is designed to measure safety, tolerability, immunogenicity and VE against heterologous controlled human malaria vaccine conducted at 3 or 12 weeks after vaccination. 3. Participants will be randomized to two study groups, vaccine and placebo, in a 3:1 ratio. Treatment assignment will be double blind; however, whether a given participant will be receiving CHMI at 3 or 12 weeks will not be blind. 4. Bias will be minimized by the randomized, double-blind design and by the inability to distinguish vaccine or placebo based on appearance, tolerability or other characteristics discernable by clinical staff or study participants. 5. The study will take approximately 6 to 8 months to complete, not including 2-3 months of recruitment. The period of follow-up for each immunized participant and placebo controls is through 8 weeks post-CHMI. 6. Study participation by individuals will last 4 to 6 months (not including screening) depending upon group assignment.