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Safety, Immunogenicity, and Protective Efficacy against Controlled Human Malaria Infection of Plasmodium falciparum Sporozoite Vaccine in Tanzanian Adults.


ABSTRACT: We are using controlled human malaria infection (CHMI) by direct venous inoculation (DVI) of cryopreserved, infectious Plasmodium falciparum (Pf) sporozoites (SPZ) (PfSPZ Challenge) to try to reduce time and costs of developing PfSPZ Vaccine to prevent malaria in Africa. Immunization with five doses at 0, 4, 8, 12, and 20 weeks of 2.7 × 105 PfSPZ of PfSPZ Vaccine gave 65% vaccine efficacy (VE) at 24 weeks against mosquito bite CHMI in U.S. adults and 52% (time to event) or 29% (proportional) VE over 24 weeks against naturally transmitted Pf in Malian adults. We assessed the identical regimen in Tanzanians for VE against PfSPZ Challenge. Twenty- to thirty-year-old men were randomized to receive five doses normal saline or PfSPZ Vaccine in a double-blind trial. Vaccine efficacy was assessed 3 and 24 weeks later. Adverse events were similar in vaccinees and controls. Antibody responses to Pf circumsporozoite protein were significantly lower than in malaria-naïve Americans, but significantly higher than in Malians. All 18 controls developed Pf parasitemia after CHMI. Four of 20 (20%) vaccinees remained uninfected after 3 week CHMI (P = 0.015 by time to event, P = 0.543 by proportional analysis) and all four (100%) were uninfected after repeat 24 week CHMI (P = 0.005 by proportional, P = 0.004 by time to event analysis). Plasmodium falciparum SPZ Vaccine was safe, well tolerated, and induced durable VE in four subjects. Controlled human malaria infection by DVI of PfSPZ Challenge appeared more stringent over 24 weeks than mosquito bite CHMI in United States or natural exposure in Malian adults, thereby providing a rigorous test of VE in Africa.

SUBMITTER: Jongo SA 

PROVIDER: S-EPMC6090339 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Safety, Immunogenicity, and Protective Efficacy against Controlled Human Malaria Infection of <i>Plasmodium falciparum</i> Sporozoite Vaccine in Tanzanian Adults.

Jongo Said A SA   Shekalaghe Seif A SA   Church L W Preston LWP   Ruben Adam J AJ   Schindler Tobias T   Zenklusen Isabelle I   Rutishauser Tobias T   Rothen Julian J   Tumbo Anneth A   Mkindi Catherine C   Mpina Maximillian M   Mtoro Ali T AT   Ishizuka Andrew S AS   Kassim Kamaka Ramadhani KR   Milando Florence A FA   Qassim Munira M   Juma Omar A OA   Mwakasungula Solomon S   Simon Beatus B   James Eric R ER   Abebe Yonas Y   Kc Natasha N   Chakravarty Sumana S   Saverino Elizabeth E   Bakari Bakari M BM   Billingsley Peter F PF   Seder Robert A RA   Daubenberger Claudia C   Sim B Kim Lee BKL   Richie Thomas L TL   Tanner Marcel M   Abdulla Salim S   Hoffman Stephen L SL  

The American journal of tropical medicine and hygiene 20180621 2


We are using controlled human malaria infection (CHMI) by direct venous inoculation (DVI) of cryopreserved, infectious <i>Plasmodium falciparum</i> (Pf) sporozoites (SPZ) (PfSPZ Challenge) to try to reduce time and costs of developing PfSPZ Vaccine to prevent malaria in Africa. Immunization with five doses at 0, 4, 8, 12, and 20 weeks of 2.7 × 10<sup>5</sup> PfSPZ of PfSPZ Vaccine gave 65% vaccine efficacy (VE) at 24 weeks against mosquito bite CHMI in U.S. adults and 52% (time to event) or 29%  ...[more]

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