Experimental Malaria Vaccine Provides Protection Against Multiple Strains

An investigational malaria vaccine has protected a small number of healthy U.S. adults from infection with a malaria strain different from that contained in the vaccine, according to a study published Feb. 21 in the Proceedings of the National Academy of Sciences. NIAID sponsored and co-conducted the phase 1 clinical trial.

Malaria is transmitted to humans through the bite of infected mosquitoes, which inject immature malaria parasites called sporozoites into a person’s bloodstream. The parasites travel to the liver, where they mature, multiply and spread via the bloodstream throughout the body causing malaria symptoms including chills, fever, headache, nausea, sweating and fatigue.

According to the World Health Organization, 214 million people were infected with malaria globally in 2015 and 438,000 people died, mostly young African children. The species Plasmodium falciparum is the most common cause of malaria morbidity and mortality in Africa. In the United States, travel-related malaria is a concern for international tourists, aid workers and military personnel worldwide.

The PfSPZ vaccine used in this study was developed by Sanaria Inc., of Rockville. It contains weakened P. falciparum sporozoites that do not cause infection but are able to generate a protective immune response against live malaria infection. Earlier research at the Clinical Center with the vaccine found it to be safe, well-tolerated and protective for more than a year when tested in healthy U.S. adults against a single Africa-derived malaria strain matched to the PfSPZ vaccine.

“An effective malaria vaccine will need to protect people living in endemic areas against multiple strains of the mosquito-borne disease,” said NIAID director Dr. Anthony Fauci. “These new findings showing cross-protection with the PfSPZ vaccine suggest that it may be able to accomplish this goal.”