Wednesday, January 23, 2008
Researchers from the University of Maryland School of Medicine and the University of Bamako in Mali, Africa, have found that a new vaccine to prevent malaria has a good safety profile and stimulates a strong immune response. In the first test of the vaccine among people at risk of contracting malaria, 60 adults in Bandiagara, Mali, took part in an early clinical trial to assess the vaccine’s safety and its ability to generate specific antibodies that block the replication of parasites in the blood. The results of the study are published in the January 23, 2008, edition of the journal PLoS ONE.
"Malaria remains a major global killer, especially of infants and children, and is a serious threat to travelers," says Christopher V. Plowe, M.D, a professor of medicine at the University of Maryland School of Medicine and co-principal investigator on the study. "In this trial, we tested a blood stage vaccine, which attempts to block the malaria parasite from getting into the blood cell. It isn’t expected to completely prevent the infection, but rather to blunt the parasite’s ability to multiply and cause disease."
"We found that the malaria vaccine was well-tolerated and produced a potent immune response," says Mahamadou Thera, M.D., M.P.H., an associate professor of parasitology at the University of Bamako, and the study’s principal investigator. "In the group of volunteers who received a full-dose of the vaccine, we actually saw more than a six-fold increase in the level of parasite-blocking antibodies produced by the immune system."
Researchers from the University of Bamako’s Malaria Research and Training Center and the University of Maryland School of Medicine’s Center for Vaccine Development enrolled 60 adults between the ages of 18 and 55 in the clinical trial. It was conducted in 2004 at the Bandiagara Malaria Project in Mali’s Dogon Country. The participants were randomly assigned to one of three groups. The study groups received the malaria vaccine in either a half dose or a full dose, and the control group received a licensed vaccine that prevents rabies, which is also prevalent in the area. Both vaccines were given in three administrations about 30 days apart.
The volunteers were followed closely for any side effects as well as to measure the vaccine’s ability to produce specific antibodies that attack malaria parasites. At the end of the trial, adults who were given the malaria vaccine were offered the rabies vaccine so that all participants in the study would benefit from protection against rabies.
According to Dr. Thera, the research team is now testing the full dose malaria vaccine in a group of 400 children in Mali to assess its ability to prevent malaria disease. "If the results of that trial are promising, this vaccine could become part of a multi-component vaccine. By combining two or more parasite proteins in the same vaccine, we hope that a high level of protection against malaria disease and death can be achieved," says Dr. Thera.
The vaccine tested was developed by the Walter Reed Army Institute of Research and GlaxoSmithKline Biologicals and was first tested in healthy volunteers at the Army Institute in Maryland before being tested in Mali. The trial was supported by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, the U. S. Agency for International Development and the U. S. Military Malaria Vaccine Program. GlaxoSmithKline Biologicals provided the proprietary Adjuvant System.