Induction of malaria in volunteers by intradermal injection of cryopreserved Plasmodium falciparum sporozoites

BACKGROUND Vaccines and new drugs are needed to prevent nearly one million deaths and hundreds of millions of cases caused by Plasmodium falciparum (Pf) malaria annually. To accelerate development of these vaccines and drugs, volunteers are infected by the bites of Pf sporozoite (SPZ)-infected mosquitoes under controlled conditions. Such infections are limited to the few centers with production of PfSPZ-infected mosquitoes. We assessed the capacity to infect volunteers by intradermal (ID) injection of aseptic, purified, vialed, cryopreserved PfSPZ (PfSPZ Challenge), produced by Sanaria Inc.