Research moves toward malaria vaccine

A new push funded by the Gates Foundation is targeting the formidable parasite.

By Susan J. Landers, amednews staff. April 2, 2001.

Washington -- Malaria. It is one of the world's most prevalent and deadly diseases. The World Health Organization estimates that between 300 million and 500 million people are infected annually, 1 million to 3 million die each year, and 2.3 billion are at risk of the illness, transmitted through the bite of the Anopheles mosquito.

But recently, stepped-up attention has resulted from public and private initiatives, advancing prospects for the development of a malaria vaccine.

The heightened interest has likely been sparked by the increasing globalization of the economy, coupled with the recognition that malaria is a significant problem for a large portion of the world's population, said Lee Hall, MD, PhD, chief of the Malaria Vaccine Development Section at the National Institute of Allergy and Infectious Diseases.

For instance, the National Institutes of Health has increased funding for the quest and, most recently, vaccine manufacturers and research centers are joining with a nonprofit group that is spearheading efforts to produce a vaccine.

GlaxoSmithKline has been working on a vaccine since 1983. The firm's product is considered a promising treatment for protecting children against a strain of the parasite endemic to most of the African continent.

In addition, Apovia Inc., a San Diego-based biotechnology company, and the Emory University Vaccine Research Center in Atlanta, have also formed partnerships with the Malaria Vaccine Initiative. The NIAID signed an agreement to work on this project.

"I think there are reasons to be optimistic over the latest efforts," said Dr. Hall. "We know that, over time, people in endemic areas become progressively less ill with subsequent infections. We know that people who have been exposed to the infectious stage actually are protected against subsequent infection. We know that you can transfer protection with serum and we know that there are animal models in which you can achieve protection," he said.

"But trying to translate those findings into a vaccine that works faces a lot of barriers," said Dr. Hall.

Children younger than 5 and pregnant women are among those most vulnerable. "Our hope is that the protection we have seen in adults will translate into life-saving protection in children," said Regina Rabinovich, MD, director of the Malaria Vaccine Initiative.

In an initial trial of its product, GlaxoSmithKline found that six of seven U.S. Army volunteers were protected from malaria. In addition, a field trial in adult men in the West African nation of Gambia showed an efficacy rate of 70% in providing protection over a short period.

An infusion of capital

The Malaria Vaccine Initiative was established in 1999 by the Program for Appropriate Technology in Health, or PATH, a U.S.-based nonprofit organization, using a $50 million award from the Bill and Melinda Gates Foundation.

The initiative sprang from the belief that the technology and knowledge needed to create a vaccine exist, but that market forces alone would not lead to its aggressive development, mostly because the disease is particularly prevalent in the poorer countries of the world. Sub-Saharan Africa has the majority of the world's malaria cases, but the disease is also found in India, Southeast Asia and South and Central America.

Christopher Plowe, MD, MPH, head of the malaria section of the University of Maryland Center for Vaccine Development, gives credit for the new research efforts to the Gates Foundation, as well as the Clinton administration and Congress for boosting NIH funding.

"But I think it's really hard to predict when we are going to have a successful product because there is no precedent for a successful vaccine against a parasite like this. It's a very clever parasite," he noted.

Stephen Hoffman, MD, senior vice president for immunotherapeutics at Celera Genoma Corp., agrees that the organism that causes malaria is much more complex than the viruses or bacteria against which we have vaccines.

The malaria parasite also has four different stages to its life cycle and it changes itself, said Dr. Hoffman. "So you have to make a vaccine against all the stages of the life cycle."

Although Dr. Hoffman applauds the new effort, he also regrets the historically scant resources. "Given the magnitude of the problem, the investment in malaria research has been minuscule," he said.