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Have Researchers Finally Developed a Malaria Vaccine That Won't Fail?

A US government-funded malaria vaccine is effective in human trials.
U.S. Army volunteers administer a malaria vaccine clinical trial in 2010. Photo: U.S. Army

Time after time, the world has gotten its hopes up as scientists have suggested they've been close to developing a malaria vaccine. And time after time, the world has been disappointed. Well, it's time to get your hopes up again: Thursday, the National Institutes of Health announced that they've found a "safe and protective" vaccine for the disease.

In human trials, 12 of 15 people who were given high dosages of the vaccine were protected against malaria infection. It's just a Phase I trial, and even if everything goes according to plan, it could take another decade before the vaccine is ready for widespread distribution. But Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the trial was "an important step forward."

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"Scientists and health care providers have made significant gains in characterizing, treating, and preventing malaria," he said. "However, a vaccine has remained an elusive goal."

He's not kidding. Malaria vaccines have failed in mice, and they've failed in humans. They've failed early in development and they've failed late in development. Well-funded trials have failed and other vaccines have failed due to lack of funding. Failures have been seen as glimmers of hope and huge disappointments.

According to the World Health Organization, 219 million cases of malaria caused at least 660,000 deaths in 2010. The unofficial count could be much higher, because many who die aren't diagnosed. That number is down from 985,000 deaths in 2000, a development caused by better mosquito bed netting distribution and better prophylactic treatment.

But despite the incredible sums of money being spent on vaccine development—Bill Gates has spent hundreds of millions alone—nothing has worked yet. Earlier this year, Gates famously said it was his mission to eradicate malaria: "Someday [malaria] will become a disease like smallpox, like polio that won't be killing anyone."

Last year, a vaccine funded by Gates' foundation protected only 30 percent of those vaccinated in Africa's largest clinical trial. That's how many of these trials have gone: Even the most successful ones only protect a small percentage of people from the parasite.

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By definition, creating a vaccine to prevent a protozoan disease is more difficult than creating one to protect against a viral or bacterial infection. But it's not impossible: There have still been several successful vaccines for protozoan diseases. Last year, researchers developed the first effective vaccine for visceral leishmaniasis, a disease that has a 90 percent mortality rate and infects roughly 500,000 people each year.

Protozoa are generally more complex creatures than viruses or bacteria. Malaria, for instance, has several different developmental stages that make it tough for scientists to know which stage to attack. That's led to dozens and dozens of potential vaccines, all of which haven't worked as well as their developers hoped. The WHO lists dozens of active malaria vaccine projects and even more inactive ones. Many of them are work with completely different mechanisms of action.

Deb Derrick, president of Friends of the Global Fight Against AIDS, Tuberculosis, and Malaria, says those failures were all necessary to narrow down the list of possible solutions.

"I've seen clinical trials come and go and investments come and go. It's an expensive and longwinded process coming up with a vaccine. There's 99 failures for every success, but that failure is part of the process," she said. "With this one, the fact that they had such a high rate of effectiveness without bad side effects is tremendously encouraging."

The NIH trial is not without red flags, however. The vaccine was barely effective in smaller doses, which means booster shots or larger doses will need to be administered, which can drive up cost and decrease enrollment. Secondly, the vaccine needs to be injected directly into the bloodstream. That's not a problem if you're getting it in a hospital or clinic, but that means whoever is giving the vaccine will need to be specially trained. Self administration, at this point, is not an option.

But the fact that the NIH and the U.S. Department of Defense are behind this, and malaria's long list of deep-pocketed enemies, make it unlikely that funding will be an issue going forward.

"Even in constrained budgets we have bipartisan support for this kind of technology," Derrick said. "If funding goes up, the number of deaths drops. It's easily correlated—that's the kind of investment we like making."