A female Anopheles albimanus mosquito feeding on a human host. Early results from a major clinical trial in Africa show a malaria vaccine has reduced the risk for children by nearly 50%.
Credit: James Gathany/U.S. Centres for Disease Control and Prevention
WASHINGTON: Early results from a major clinical trial for a malaria vaccine were released yesterday, and show it is capable of cutting risk by nearly 50% in African children.
The vaccine known as RTS,S is made by the British pharmaceutical giant GlaxoSmithKline's lab in Belgium, and is the first of its kind to attempt to block a parasite, rather than bacteria or viruses.
Experts hailed the phase III trial under way at 11 sites in sub-Saharan Africa as a promising step toward eradicating the ancient mosquito-borne disease that kills almost 800,000 people annually, with children being particularly susceptible.
The results are published online in The New England Journal of Medicine, and were simultaneously announced at the Malaria Forum hosted by the Bill & Melinda Gates Foundation in Seattle, Washington.
In a statement, philanthropist and Microsoft tycoon Bill Gates described the findings as a "huge milestone" in the fight against malaria, which "has the potential to protect millions of children and save thousands of lives."
The first parasite vaccine?
Children aged five to 17 months who received three doses of the vaccine saw a 56% lower risk of developing clinical malaria, which causes high fever and chills, according to the study.
When it came to severe malaria - the stage of the illness that can be fatal and reaches the blood, brain or kidneys - those who received the vaccine showed a 47% lower risk.
"This is remarkable when you consider that there has never been a successful vaccine against a human parasite," said Tsiri Agbenyega, who chairs the RTS,S Clinical Trials Partnership and heads malaria research at Komfo-Anokye Teaching Hospital in Kumasi, Ghana. "While these results are encouraging, we still have a ways to go."
More data needed for youngest infants
The analysis was done with data from 6,000 children in the trial over a 12-month follow up after vaccination.
More data is needed from the younger age group - infants aged six to 12 weeks - to better assess how well it works in this particularly vulnerable group, experts said. Additional results from the younger set are due next year.
The World Health Organization says malaria claimed 781,000 lives in 2009. About 90 percent of malaria deaths each year occur in Africa and 92 percent of those are children less than five years old.
Asked whether the Gates Foundation would get behind a vaccine with a success rate of only about half, Regina Rabinovich, director for infectious diseases at the foundation's global health program, was circumspect.
"This is a key question. The group will ultimately want to understand efficacy, duration and safety," she said, adding she was "enthusiastic" about the results so far and was awaiting further data.
