Testing Pfs25-EPA/Alhydrogel as a Potential Malaria Transmission Blocking Vaccine

Summary

Background: \- Malaria is a disease that is spread by mosquitoes. Researchers are looking for a vaccine that can prevent mosquitoes from transmitting malaria to people. They want to test a vaccine called Pfs25-EPA/Alhydrogel that may help stop malaria parasites from developing in mosquitoes. When a mosquito bites a vaccinated person, the vaccine should prevent parasites from developing in the mosquito. As a result, the mosquito will not spread malaria to the next person it bites. However, the vaccine will not directly prevent people vaccinated from getting sick with malaria. Researchers want to test this vaccine in people who live in rural Mali. To do so, the study will compare the symptoms and the blood tests of the participants who receive either the study vaccine or a regular hepatitis B/meningococcal vaccine. Objectives: \- To see if Pfs25-EPA/Alhydrogel is a safe and effective malaria vaccine. Eligibility: \- Healthy volunteers between 18 and 45 years of age who live in Bancoumana, Mali. Design: * Participants will be screened with a medical history, physical exam, and blood tests. * Participants will be separated into two groups. One group will have Pfs25-EPA/Alhydrogel to test the study vaccine. The other group will have the regular Hepatitis B vaccine series, meningococcal vaccine. * In the study vaccine group, participants will have either a lower dose or a higher dose. For the lower dose, they will have two vaccine shots over 1 year. For the higher dose, they will have four vaccine shots over about 14 months. * In the other vaccine group, participants will have the Hepatitis B vaccine series, meningococcal vaccine according to the standard dose schedule. * All participants will provide regular blood samples for testing during the study. * Participants who develop malaria during the study will participate in evaluation of transmission and parasite development of malaria parasite from the person to mosquito via transmission assays. They will allow mosquitoes (that have no diseases) to bite them in a controlled clinic setting. This will let researchers see if the vaccine can stop the mosquitoes from carrying malaria to other people.

Timeline

Start

2013-03-27

Primary completion

2015-12-22

Completion

2016-12-19

Publications

• Background Kaslow DC. Transmission-blocking vaccines. Chem Immunol. 2002;80:287-307. doi: 10.1159/000058850. No abstract available.
• Background Williamson KC, Keister DB, Muratova O, Kaslow DC. Recombinant Pfs230, a Plasmodium falciparum gametocyte protein, induces antisera that reduce the infectivity of Plasmodium falciparum to mosquitoes. Mol Biochem Parasitol. 1995 Dec;75(1):33-42. doi: 10.1016/0166-6851(95)02507-3.
• Background Diallo M, Toure AM, Traore SF, Niare O, Kassambara L, Konare A, Coulibaly M, Bagayogo M, Beier JC, Sakai RK, Toure YT, Doumbo OK. Evaluation and optimization of membrane feeding compared to direct feeding as an assay for infectivity. Malar J. 2008 Dec 2;7:248. doi: 10.1186/1475-2875-7-248.
• Sagara I, Healy SA, Assadou MH, Gabriel EE, Kone M, Sissoko K, Tembine I, Guindo MA, Doucoure M, Niare K, Dolo A, Rausch KM, Narum DL, Jones DL, MacDonald NJ, Zhu D, Mohan R, Muratova O, Baber I, Coulibaly MB, Fay MP, Anderson C, Wu Y, Traore SF, Doumbo OK, Duffy PE. Safety and immunogenicity of Pfs25H-EPA/Alhydrogel, a transmission-blocking vaccine against Plasmodium falciparum: a randomised, double-blind, comparator-controlled, dose-escalation study in healthy Malian adults. Lancet Infect Dis. 2018 Sep;18(9):969-982. doi: 10.1016/S1473-3099(18)30344-X. Epub 2018 Jul 27.

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