March 9, 2007

Investigators testing vaccine to slow malaria’s global march

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Investigators testing vaccine to slow malaria’s global march

Infectious diseases researchers at Vanderbilt Medical Center are seeking healthy adults to help test a vaccine for malaria.

While malaria is no longer considered a threat within U.S. borders, according to the World Health Organization (WHO) the disease kills more than 1 million people around the globe each year. Most of its victims are children.

“Obviously people are not going to be exposed to malaria here in Nashville. But the burden of this disease worldwide is enormous,” said Kathryn Edwards, M.D., vice chair of Pediatric Research. “We are seeking those individuals who would be willing to step up to assist others elsewhere on our planet who really need our help.”

Presently, VUMC researchers are the only team of vaccine investigators in the nation who are testing a newly developed malaria vaccine currently being referred to as Adenovirus Type 35 Based Circumsporozoite Malaria Vaccine. The vaccine is designed to induce a cell-mediated immunity, thereby preventing the parasite which causes malaria from entering and developing within the liver of those who become infected.

Forty percent of the Earth's population — primarily those inhabiting the poorest countries — remain at risk of contracting malaria each year. The disease remains one of the top global health and economic threats. In addition to more than 1 million deaths annually, the WHO estimates malaria causes at least 300 million acute illnesses. Economists estimate the global economic impact of malaria at billions of dollars each year in the form of lost economic growth and development.

Malaria is caused by a one-celled parasite called a plasmodium, which is spread to humans from the bite of a female Anopheles mosquito. The mosquito is driven to hunt because it requires blood to produce its offspring, and for some reason not fully understood, prefers human blood over other animals.

“Malaria is an enormous global problem. It is one of the major killers of children in Africa and the Far East,” said Edwards. “The global health community is really having a problem with this disease because mosquitoes are becoming more resistant to DDT and the malaria parasite is becoming resistant to antimalarials.”

At this phase of testing, Edwards and her research team are studying this vaccine to see whether it can produce a response to one of the malaria's major proteins.

“If indeed this works, we would begin to work with scientists in Africa to begin to study the vaccine in children,” she said.

For this study Edwards said an additional 90 vaccine trial volunteers are needed beyond those already recruited. Since malaria isn't a threat, or even widely acknowledged within the United States anymore, enrollment will come from volunteers who have a global perspective and really want to help people in other countries.

“We are hoping for a number of volunteers between the ages of 18 and 45 years of age who are in good health who would be willing to help us,” she said.

For more information about the malaria vaccine trial, contact Tanya Davis at 343-2327 or Lisa Sherden at 322-2787 or e-mail