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Safety, Immunogenicity, and Protective Efficacy of Intradermal Immunization with Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites in Volunteers Under Chloroquine Prophylaxis: A Randomized Controlled Trial
- Source :
- American Journal of Tropical Medicine and Hygiene; 663; 673; 0002-9637; 3; 94; ~American Journal of Tropical Medicine and Hygiene~663~673~~~0002-9637~3~94~~
- Publication Year :
- 2016
-
Abstract
- Contains fulltext : 171457.pdf (publisher's version ) (Open Access)<br />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 3x monthly immunizations with 7.5 x 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 x 10(5) PfSPZ-CVac was safe, but induced only minimal immune responses and no sterile protection against Pf CHMI.
Details
- Database :
- OAIster
- Journal :
- American Journal of Tropical Medicine and Hygiene; 663; 673; 0002-9637; 3; 94; ~American Journal of Tropical Medicine and Hygiene~663~673~~~0002-9637~3~94~~
- Publication Type :
- Electronic Resource
- Accession number :
- edsoai.on1284154065
- Document Type :
- Electronic Resource