The race to develop Ebola vaccines closed in on the finish line this year, as scientists tested two candidates that could ultimately be stockpiled for future outbreaks. Both vaccines target a protein made by Zaire ebolavirus, the virus that raged through West Africa in 2014 and early 2015, killing more than 11,000 people (SN: 12/27/14, p. 14). The epidemic now appears under control across West Africa, with only a few cases in Liberia.
One vaccine relies on a live, replicating virus to stimulate an immune response in patients. In August, researchers testing it reported results from the largest Ebola vaccine trial to date to show evidence of protection: a study of 7,651 Guinean adults. None of the people vaccinated immediately after a close contact was diagnosed with Ebola became infected with the virus (SN: 9/5/15, p. 6).
The other vaccine uses a virus that can’t replicate. In November, Myron Levine, a vaccine researcher at the University of Maryland School of Medicine in Baltimore, and his colleagues demonstrated the vaccine’s safety in a trial of U.S. and West African participants. A single high dose was enough to rally molecular troops to fight the virus, the team reported in the Lancet Infectious Diseases.
Among the vaccines in the works, Levine says, these two are the frontrunners and may be close to receiving approval from the U.S. Food and Drug Administration. “I’m hoping that in 2016 we see the two main first vaccines approved,” Levine says.