New Malaria Vaccine Is Shown to Work in Infants Under 1 Year Old, a Study Finds
The world’s most promising malaria vaccine has been shown to work in infants less than a year old, the most vulnerable group, according to a study being published today.
The study, being published in The Lancet, a British medical journal, was small, comprising only 214 babies in Mozambique, and intended to show only that the vaccine was safe at such young ages. But it also indicated that the risk of catching malaria was reduced by 65 percent after the full course of three shots.
“We’re now a step closer to the realization of a vaccine that can protect African infants,” said Dr. Pedro Alonso, the University of Barcelona professor who leads clinical trials of the GlaxoSmithKline vaccine.
If it passes much larger clinical trials set to start in seven countries next year, and if it is accepted by national regulatory agencies, it could be ready for distribution by 2012, said Dr. W. Ripley Ballou, Glaxo’s vice president for international clinical trials.
In 2004, Dr. Alonso showed for the first time that the vaccine could protect children against infection or death. That study of 2,022 children aged 1 to 4 showed protection from infection about 45 percent of the time.
Such a relatively low level of protection would not be acceptable in a vaccine in the West, but malaria is a leading killer of African children, so even imperfect coverage is a major public health victory.
The vaccine, presently known as RTS,S and tentatively brand-named Mosquirix, is made by fusing a bit of outer protein of the deadly falciparum strain of the malaria parasite with a bit of hepatitis B virus and a chemical booster — the latter two added to provoke a stronger immune reaction.
At least nine malaria vaccine candidates are in development, but Mosquirix is the furthest along. Glaxo has been refining it for 20 years and expects to have spent up to $600 million on it by the time it comes to market. About $100 million has been paid by the Bill and Melinda Gates Foundation through the PATH Malaria Vaccine Initiative.
No decision has been made about the price to be offered to poor countries and international health agencies. But “if a child will benefit, price will not stand in the way,” said Dr. Christian Loucq, director of the vaccine initiative.
The vaccine is given in three injected doses. That is an obstacle in poor countries, which have difficulties immunizing even against polio — done with oral drops requiring no medical skill.
But even one dose has some protective effect, the Lancet study found.
It is unknown how long protection lasts. But because the youngest children are the most vulnerable, Dr. Alonso said, vaccination buys them time to build up natural immunity, which is acquired by surviving multiple mosquito bites.