1. Safety, Immunogenicity, and Protective Efficacy of Intradermal Immunization with Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites in Volunteers Under Chloroquine Prophylaxis: A Randomized Controlled Trial
- Author
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Bastiaens, Guido JH, van Meer, Maurits PA, Scholzen, Anja, Obiero, Joshua M, Vatanshenassan, Mansoureh, van Grinsven, Tim, Sim, B Kim Lee, Billingsley, Peter F, James, Eric R, Gunasekera, Anusha, Bijker, Else M, van Gemert, Geert-Jan, van de Vegte-Bolmer, Marga, Graumans, Wouter, Hermsen, Cornelus C, de Mast, Quirijn, van der Ven, André JAM, Hoffman, Stephen L, and Sauerwein, Robert W
- Subjects
Medical Microbiology ,Biomedical and Clinical Sciences ,Clinical Sciences ,Prevention ,Vaccine Related ,Malaria Vaccine ,Vector-Borne Diseases ,Rare Diseases ,Infectious Diseases ,Malaria ,Immunization ,Infection ,Good Health and Well Being ,Adolescent ,Adult ,Animals ,Anopheles ,Antimalarials ,Chloroquine ,Cryopreservation ,Double-Blind Method ,Humans ,Injections ,Intradermal ,Insect Bites and Stings ,Malaria ,Falciparum ,Male ,Patient Safety ,Plasmodium falciparum ,Sporozoites ,Young Adult ,Medical and Health Sciences ,Tropical Medicine ,Biomedical and clinical sciences ,Health sciences - Abstract
Immunization of volunteers under chloroquine prophylaxis by bites of Plasmodium falciparum sporozoite (PfSPZ)-infected mosquitoes induces > 90% protection against controlled human malaria infection (CHMI). We studied intradermal immunization with cryopreserved, infectious PfSPZ in volunteers taking chloroquine (PfSPZ chemoprophylaxis vaccine [CVac]). Vaccine groups 1 and 3 received 3× monthly immunizations with 7.5 × 10(4) PfSPZ. Control groups 2 and 4 received normal saline. Groups 1 and 2 underwent CHMI (#1) by mosquito bite 60 days after the third immunization. Groups 3 and 4 were boosted 168 days after the third immunization and underwent CHMI (#2) 137 days later. Vaccinees (11/20, 55%) and controls (6/10, 60%) had the same percentage of mild to moderate solicited adverse events. After CHMI #1, 8/10 vaccinees (group 1) and 5/5 controls (group 2) became parasitemic by microscopy; the two negatives were positive by quantitative real-time polymerase chain reaction (qPCR). After CHMI #2, all vaccinees in group 3 and controls in group 4 were parasitemic by qPCR. Vaccinees showed weak antibody and no detectable cellular immune responses. Intradermal immunization with up to 3 × 10(5) PfSPZ-CVac was safe, but induced only minimal immune responses and no sterile protection against Pf CHMI.
- Published
- 2016