The World Health Organization (WHO) on Wednesday approved the first malaria vaccine after a study that included hundreds of thousands of children across sub-Saharan Africa showed encouraging results.

Cheat sheets: Evidence-based medicine 101

Background

According to Vox, malaria is not usually fatal with treatment, and death rates for the disease have fallen by about 50% since 2000. However, the disease still causes 220 million infections every year, primarily in sub-Saharan Africa, and causes an estimated 400,000 fatalities per year—including about 260,000 children under the age of 5. (In comparison, America generally has only about 2,000 cases per year, primarily from people returning from areas where the disease is prevalent.)

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According to Mary Hamel, wholeads the WHO's malaria vaccine implementation program, severe malaria makes up about half of malaria deaths and is considered "a reliable proximal indicator of mortality."

Widespread measures such as the use of mosquito nets treated with insecticide, preventive treatments, and indoor spraying have helped lower deaths from the disease since 2000 in areas where it is common. However, these measures do not prevent severe infection and death as effectively as the newly approved malaria vaccine has in clinical trials, the New York Times reports.

Noting that "[p]rogress against malaria has really stalled over the last five or six years," Ashley Birkett, head of malaria programs at PATH, a nonprofit organization focused on global health, said this new vaccine carries with it a "potential for very, very significant impact."

Details on the new vaccine

GlaxoSmithKline's new vaccine, Mosquirix or RTS,S, is not only the first malaria vaccine to be approved by the WHO, but it is also the first vaccine for any type of parasitic disease, the Times reports.

The drug is administered in four doses, three of which are administered one month apart and the final one given a year later. The drug has few serious side effects, Vox reports, and costs roughly $5 per dose.

In clinical trials, the vaccine prevented around 40% of cases and 30% of severe cases. And while that prevention rate is lower than most vaccines for early childhood disease—such as the measles vaccine, which is 97% effective—it can significantly cut down on the number of fatalities each year from the disease. It is also significantly more effective than existing preventive measures alone, Vox reports.

In fact, according to Vox­, recent research that modeled the effects of a broad Mosquirix rollout estimated that "5.3 million cases and 24,000 deaths could be averted" if the 30 million people who are most at risk could receive the vaccine each year.

Overall, according to Hamel, over 2.3 million doses have already been administered, reaching more than 800,000 children—bringing the percentage of children protected against malaria in some way from under 70% to over 90%.

'A historic event'

After a 100-year quest to develop a malaria vaccine that is safe, moderately effective, and ready for distribution, the approval of this vaccine is "a historic event," according to Pedro Alonso, director of the WHO's global malaria program.

WHO's approval opens the door for Gavi, the global vaccine alliance, to assess whether it is a worthwhile investment. If Gavi approves the vaccine, the organization will then purchase the vaccine for nations that request it—a process that could take at least a year, the Times reports.

That said, because the vaccine can be administered with other childhood vaccinations, experts do not expect the rollout of the vaccine—if fully approved and distributed—will be challenging. "We aren't going to have to spend a decade trying to figure out how to get this to children," Hamel said.

"We still have a very long road to travel, but this is a long stride down that road," Tedros Adhanom Ghebreyesus, WHO director-general, said at a news conference on Wednesday. (Piper, Vox, 10/6; Mandavilli, New York Times, 10/7)