Safety, tolerability and immunogenicity in age de-escalation of PfSPZ Vaccine in Equatorial Guinea (EGSPZV2)

This trial will evaluate the safety, tolerability, and immunogenicity of PfSPZ Vaccine in healthy Equatoguinean adults, adolescents, children and infants who receive doses of 0.9x10^6, 1.8x10^6 or 2.7x10^6 PfSPZ Vaccine via direct venous inoculation (DVI) compared with control groups receiving normal saline (NS) placebo by DVI. In addition, the study will also assess a second PfSPZ-based vaccination approach known as PfSPZ-CVac- the administration of non-irradiated, infectious PfSPZ (PfSPZ Challenge) (1x10^5 PfSPZ) under anti-malarial chemoprophylaxis (chloroquine) in younger adults ages 18 to 35 years for safety, tolerability, immunogenicity and efficacy against controlled human malaria infection (CHMI).