Safety, Tolerability, and Immunogenicity of Plasmodium falciparum Sporozoite Vaccine Administered by Direct Venous Inoculation to Infants and Young Children

KSPZV1 Part 1 is a single center, age de-escalating, dose-escalating, randomized, double-blind, placebo-controlled trial enrolling malaria-exposed Kenyan children ages 5 months to 9 years at the time of first vaccination. One or two doses of the radiation-attenuated sporozoite-based PfSPZ Vaccine (8 per group) or normal saline placebo (4 per group) were administered by DVI at up to 5 different dosing levels using a staggered, dose-escalating design. Dosages include: 1.35 x10^5, 2.7 x10^5 (lowest two doses only in the two younger age groups), 4.5 x10^5, 9.0 x10^5, and 1.8 x10^6 PfSPZ in 13 cohorts of 12 participants each (3 dose cohorts among 5–9-year-olds, 5 among 1–5-year-olds, and 5 among 5–12-month-olds).