The recent Ebola epidemic claimed 11,000 lives in west Africa and inspired panic across the globe at the prospect of the unrelentingly contagious and devastatingly lethal virus would invade communities. Now, scientists who have been working on a shield against it believe that an outbreak of that scale will never terrorize Africa, or the world, ever again. Developed in the midst of the pandemonium surrounding the the pathogen that infected more than 30,000, the Ebola vaccine will be available to the public after it's approved by regulatory agencies, pending additional testing and eventual Food and Drug Administration approval, but experts are convinced it's a potential "game-changer."
Research from such varied international partner agencies as the World Health Organization, Guinea's Ministry of Health, and Public Health England conducted the trials in Guinea, one of the epicenters of the outbreak, in 2015 and 2016. By January 2016, Ebola will have killed 2,536 people in that country alone, but the spread was on the decline by the time the study launched. So, scientists used a "ring vaccination" method to test the drug, identifying the contacts of those known to have been infected and initially immunizing some of them right away and others three weeks later, according to The Guardian. It was soon apparent that the adults who received the vaccine were infected, so the researchers administered it to all the adults in the study, and expanded it to children, too.
The Washington Post reported that the scientists are currently also conducting testing in Sierra Leone and Liberia, the two other West African countries with the highest death tolls from the outbreak, which exploded in 2014. And they have every reason to be hopeful: The study's lead author and WHO Assistant Director General for health systems Marie-Paule Kieny said in announcing the results, which were published Thursday in the Lancet medical journal, that the vaccine ensures that populations will not be left "defenseless," as they previously were when there was no vaccine and no cure, according to the Post.
By many accounts, the vaccine is a one-shot miracle. Perhaps that's why it's been streamlined for regulatory approval; Merck, the company manufacturing the drug, has pledged to submit the licensing application to regulatory authorities by the end of 2017, even as researchers continue to work to ensure that it is safe for children and other vulnerable populations. According to NPR, it is predicted to be approved by both the WHO and the FDA sometime in 2018. In the meantime, Merck is committed to making available 300,000 emergency doses.
Although the scientists have reported 100 percent efficacy in its trial of about 5,000 people, that number will likely fall to between 70 and 100 percent, University of Florida biostatistician Ira Longini, who helped test the vaccine, told NPR. That's better than the flu shot's 50 percent efficacy, and it works in just four or five days. In addition, most of the reported side effects from the trial were mild: headache, fatigue, muscle pain.
Still, questions about the vaccine's long-term effectiveness linger. "One question that has not been adequately addressed, even in nonclinical studies with any Ebola virus vaccine, is with regard to durability — is the vaccine long-lasting?" Ebola virus and vaccine expert Thomas Geisbert wrote of the findings, according to Vox. "Is it still protective, for example, 2–3 years after the vaccination?"
That's a question that scientists will undoubtedly continue to explore. But, in the meantime, they've accomplished the impressive and important goals of inoculating people against the resurgence of the biggest public health crises in recent memory.