The vaccine, called RTS, S and manufactured by GlaxoSmithKline, has been in development for over 25 years, initially for the U.S. Army and now with most of its support from the Bill and Melinda Gates Foundation.
The trial is scheduled to continue through 2014 and will include tests on more than 15,000 children, from infancy onward. The first results announced at a malaria conference in Seattle on Tuesday showed that three doses protected 47 percent of the 6,000 children from 5 months to 17 months from severe malaria. (The age group was chosen for newborns have some form of protection of the antibodies from their mothers.)
“The results are encouraging, but we still have a long way to go,” said Dr. Tsiri Agbenyega, who directs malaria research in a hospital in Ghana was one of 11 research sites. Announced the results, published in the New England Journal of Medicine.
While 47 percent of protection is not very effective – most vaccines are not released until they do better than 90 percent – Glaxo CEO Andrew Witty said that the protection to both save millions of lives over a decade.
Malaria is estimated to kill about 780,000 people a year, most of them African children. Adults who survive childhood attacks usually develop at least partial immunity.
A few years ago, the World Health Organization estimates that malaria killed a million people a year, and in 2008, said mosquito nets, DDT and new artemisinin-based drugs paid for by donor countries were taking its toll. However, the estimates are controversial and change as new statistical methods are applied. In addition, malaria can bounce back awfully fast as soon as control measures are relaxed or even warmer, wetter climate.
It’s much harder to make a vaccine against parasites such as malaria, which make a virus. The malaria parasite changes the way it moves from the blood into the liver and back into the blood, and each form has different surface proteins.
Glaxo has already spent more than $ 300 million in the RTS, S, which would probably be called Mosquirix if you enter the market, and expects to spend up to $ 100 million, Mr. Witty said. Then, if the vaccine is approved, the company will cost 5 percent more for poor countries, with the benefit of 5 percent reinvested in malaria research.
Asked if the Gates Foundation would pay for a vaccine that is less than 50 percent effective, Dr. Regina Rabinovich, head of the foundation of infectious diseases, said: “Would you rather see a 100 percent effective? Obviously. But I hope that the 2014 results, and any decision we make will be for data.”
Many rival malaria vaccines, targeting different surface proteins or the use of different methods to provoke the immune system to a counterattack, are in development. Some researchers have suggested that the combination of several in a single dose or taking sequential images of different combinations to see if they are doing better.
“That could be a possibility, but it is in the works,” said Dr. Christian Loucq, director of the Initiative for the PATH Malaria Vaccine, who coordinated the RTS, S trials and is in charge of other vaccines that Gates Foundation supports.
Most pessimistic experts in the field argue that making a vaccine against malaria in the long term is impossible, because even the “perfect natural vaccine” – survive repeated bouts of malaria – fades after a few years away from the malarious area.