This is an open label, human pilot study to optimise controlled human malaria infection (CHMI) administered by Plasmodium falciparum sporozoites (PfSPZ. Volunteers will be inoculated with PfSPZ Challenge. The route of administration and dose will vary in order to identify the optimal regimen that achieves the greatest infection rate in volunteers with Plasmodium falciparum. All volunteers recruited will be healthy adults aged between 18 and 45 years. Safety and infectivity data will be collected for each of the regimens.