Study outcome measures
infection, parasitemia
ADVERSE EVENTS, PARASITEMIA, INFECTION, SECONDARY, CPS
To determine the safety and tolerability of NF135 sporozoite immunization under chemoprophylaxis, the prespecified primary endpoint was the frequency and the severity of adverse events after NF135 CPS immunization. To determine the dose-dependent protective efficacy of NF135 CPS immunizations, secondary endpoints included the number of sterilely protected participants and the time to parasitemia detectable by qPCR after homologous and heterologous NF54 challenge infection. Original secondary objectives additionally included assessment of the protective efficacy against a second heterologous strain NF166 and assessment of protection against homologous or heterologous re-challenge 1 year after immunizations in those participants protected against respectively homologous or heterologous CHMI at 19 weeks. Following the compromised immunizations in cohort A, the study protocol for cohort B was amended and received ethics approval to prioritize comparison of homologous (NF135) versus heterologous (NF54) efficacy over protection against two different heterologous strains and to perform re-challenge only if protection at 19 weeks was ≥ 50%. Ancillary endpoints included the peak parasite density and parasite density on day 7 after each immunization.