Firing new shots in the malaria war, a vaccine still in the testing stage is now a step closer to becoming a public health reality [Science News]. Two field trials in Kenya and Tanzania showed that the experimental drug reduced malaria infections by more than 50 percent in infants and young children; if a final set of trials proves that the vaccine is indeed safe and effective, the vaccine could be ready for use by 2011.
If the phase three trials are successful, it would be “an extraordinary scientific triumph,” said Dr. W. Ripley Ballou, deputy director for vaccines and infectious diseases for the Bill and Melinda Gates Foundation, which helped fund the research. But more importantly,” Ballou added, “it could save millions of children’s lives” [Los Angeles Times]. Malaria kills about 1 million people around the world each year, and most of the victims are children under the age of five.
In the two studies, both published in the New England Journal of Medicine, researchers say they didn’t expect the vaccine to be 100 percent effective against malaria, unlike vaccines against diseases like smallpox and measles. However, even partial protection would be a great advance, researchers say.
There are several types of malaria parasite, all spread among humans by mosquitoes. The vaccine, dubbed RTS,S by its maker GlaxoSmithKline, targets the protozoan Plasmodium falciparum, which causes the most severe form of the disease [Science News]. Malaria is a particularly difficult disease to fight because people can be reinfected by mosquitoes many times in their lives; current efforts to combat infections in Africa focus largely on preventative measures like mosquito nets around beds and insecticides.
The development of this promising vaccine illustrates how some deep-pocketed charities are breathing new life into research for potentially life-saving drugs that pharmaceutical companies saw as too risky or unprofitable to pursue. In 1999, as Glaxo was planning to abandon the malaria vaccine amid scepticism about markets, the Belgian unit doing the research made the unusual move of applying for a grant from the Gates Foundation. Since then, the foundation has poured some $107.6 million into developing the vaccine [The Wall Street Journal].
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Image: flickr / Julien Harneis
December 10th, 2008 at 9:32 am
The RTS,S vaccine doesn’t protect against infection, per se, but against getting sick from the infection. It’s a crucial distinction, somewhat obscured in this piece, because it means that the malaria parasite, even under universal vaccine coverage, will continue to survive and evolve.
Given that malaria parasites have figured out how to evade every drug we’ve thrown at them, sometimes in just a matter of a couple years, wouldn’t this vaccine, if implemented, be useless in a short while, too?
December 10th, 2008 at 12:34 pm
You make some good points, Sonia. As you note, the vaccine doesn’t prevent infection, instead it triggers a strong antibody response against the parasite once it has entered the bloodstream. But that’s how all vaccines work — a measles vaccine doesn’t prevent the virus from getting into the body, it teaches the immune system how to destroy the virus when it sees it.
But this malaria vaccine is a much trickier business, it’s true. Researchers really don’t know why some kids who got vaccinated still came down with malaria; study coauthor Kevin Marsh told Nature News that “no one really knows how RTS,S works.” I’ll be interested to see in the coming years whether this vaccine really can make a dent in infections, or whether the parasite finds a work-around.
March 23rd, 2010 at 1:47 pm
It is well known those same populations also have at least 11% infection rate for Borreliosis (for which they do not even test for)and HIV is out the roof. As for the evasion issue-citing resistance to antimalarials. It is no wonder and falsely proclaimed in those populations who do not have any resistance to anything. It is something to watch closely.
August 16th, 2011 at 9:14 am
The big risk with vaccines like these, who are ‘incompetent’(they cannot give full protection against a natural infection) is that it can promote more virulent strains to survive better in the population. So, people who are then unvaccinated have even more serious problems.