Navy Researchers Work on Malaria Vaccine

By Christen McCluney
Special to American Forces Press Service

Aug. 31, 2009 - Researchers at the Naval Medical Research Center are testing a malaria vaccine officials hope will protect both troops and civilians in tropical and subtropical regions afflicted by the disease. "Every minute, there are about two to three people that will die from malaria in the world," said Navy Capt. (Dr.) Judy Epstein, director of clinical trials at the Naval Medical Research Center's U.S. Military Malaria Vaccine Program.

"It is a top priority for the military to develop a vaccine," she said to "Dot Mil Docs" Pentagon Web Radio listeners Aug. 27.

Malaria affects 300 million to 500 million people throughout the world and kills about 1.5 million people per year. It occurs in many tropical and subtropical countries, including Iraq and Afghanistan. U.S. military forces are at great risk of developing malaria while deployed in endemic areas. Malaria caused more lost work days among U.S. military personnel during the 20th century than enemy fire in all conflicts in tropical regions combined, Epstein said.

The medical research center is conducting the first trial in humans of a vaccine known as PfSPZ, developed by the biotechnology company Sanaria Inc. in Rockville, Md. The trial, being conducted at both the Naval Medical Research Center and the Center for Vaccine Development at the University of Maryland's Baltimore campus, includes 104 volunteers, with 80 getting the vaccine and 24 serving as the control group. The investigators are looking at the safety, tolerability, genetic immunology and protective efficacy of the vaccine, Epstein said.

The process to create the vaccine uses mosquitoes that are infected with the parasite that causes malaria. The mosquitoes are irradiated, and the sporozoites -- cells that spread the disease -- are extracted. The vaccine is a whole-organism vaccine, using the entire parasite in a weakened form. In contrast, most malaria vaccines under development today consist of recombinant, or genetically engineered, proteins that are a part of the parasite, Epstein said.

The clinical trial tests escalating doses of vaccine to see how the participants react with each dose. When the vaccinations are complete, the participants are challenged with bites of infected mosquitoes.

"We feel that having a vaccine that could be given to troops prior to departure, and perhaps boosting before going overseas, would be tremendously useful," Epstein said. "If we develop safe and well tolerated vaccines, they could also be given to infants and have a large global impact having two benefits -- for both the military and the developing world.

"I feel extremely hopeful about this vaccine," she continued, "because it is based on the model of the irradiated sporozoite vaccine model, which is the gold standard.

It will take years and other follow-up trials before this vaccine may be available, Epstein said. "The most important thing now is to demonstrate safety and efficacy," she added.

(Christen N. McCluney works in the Defense Media Activity's emerging media directorate.)