Ancient Chinese writings noted the chilling, “wind”-like symptoms of malaria, and Greek city states recorded outbreaks that coincided with their periodic decline. Scientists have even found malaria infections in Egyptian mummies.
Efforts to defeat the deadly mosquito-borne disease have existed just as long, and today we have succeeded in eliminating it from much of the developed world. But the malaria parasite has been resilient: It is still present in 100 countries where the treatment and prevention options have proven too expensive or hard to distribute. In 2010, it infected an estimated 220 million people and still kills an average of 2,000 people every day.
But this year the first-ever malaria vaccine could be considered for regulatory approval, bringing the most promising indication so far that today’s new eradication effort could some day end in malaria’s worldwide defeat. The vaccine, known as RTS,S, has been 30-years in the making. Drug company GlaxoSmithKline and its partner, the PATH Malaria Vaccine Initiative, is now completing the final stages of trials.
To be clear, no one should believe that the RTS,S vaccine will be the holy grail to end malaria. At 11 clinical trial sites in Africa, the most recent data show that 18 months after receiving the vaccine, malaria cases dropped by 46% in children and 27% in babies. Given this partial efficacy, African governments and doctors will also have to decide whether it is worth the cost.
Nonetheless, it would mark a huge leap forward. “When you see data like that, it tells you that it’s biologically possible to make a vaccine against the disease,” says David C. Kaslow, former director of the PATH Malaria Vaccine Initiative, a global health nonprofit funded by the Gates Foundation. Even with only partial protection, Kaslow says RTS,S could reduce the massive disease burden in Africa.
And even more promising drugs may be on the way: An early-stage clinical trial showed a new vaccine with a remarkable 100% protection rate, though in an extremely small group of just six individuals who received the highest doses. Drug company Sanaria discovered how to take the natural immunity that research subjects get when bitten hundreds of times by mosquitoes with inactive malaria spores, and then trigger that same response through a vaccine.
Many questions and hurdles remain, the least of which is that it is impractical to give intravenous vaccines to millions of people. But Robert Seder, the National Institutes of Health researcher who oversaw the trial, is “optimistic” for now that these can be surmounted with enough research and development work.
"As a proof of principle, we showed that the vaccine worked, and that it was highly effective,” he says. Ten years from now he believes--“hopes”--that a home-run-type vaccine is possible.
The timeline may be of the essence. Over time, resistance is growing to existing malaria drugs and pesticide treatment methods. Says Kaslow: “Sustaining indefinitely this kind of control is going to be really tough. If you haven’t eliminated it, it can come back with a vengeance.”
[Image: Bacteria via Shutterstock]