CDC, DEBORA CARTAGENAAn experimental Ebola vaccine generated a strong immune response that protected four monkeys from lethal doses of the virus, according to results reported this week (September 7) in Nature Medicine. Researchers at the US National Institutes of Health (NIH) have now initiated clinical trials involving 20 human participants; the earliest results are expected by the end of the year.
Nancy Sullivan of the US National Institute of Allergy and Infectious Diseases (NIAID) and her coauthors created the vaccine by adding two genes from the Ebola virus to a chimpanzee cold virus; when injected into macaques, it protected the animals from an Ebola infection that was lethal to unvaccinated animals within six days. Although the immunity waned after 10 months of the initial vaccine dose, a booster shot of a different vaccine—Ebola gene segments carried by a different vector—resulted in longer-term protection.
“There is an urgent need for a protective Ebola vaccine,” NIAID director Anthony Fauci told NPR’s The Two-Way. “It is important to establish that a vaccine is safe and spurs the immune system to react in a way necessary to protect against infection.”
The vaccine was first tested on a 39-year-old woman last week, according to BBC News. Subsequent tests in various parts of the world are planned against specific strains of the Ebola virus. Even with the single primary vaccine dose, “the degree of protection seen . . . was still pretty impressive, especially when the animals received Ebola virus within a few weeks of vaccination,” virologist Jonathan Ball of the University of Nottingham told the BBC. “This is important as it would keep the dosing regimen simple and could still provide good protection in the sort of outbreak that we are seeing in Western Africa at the moment.”
As the Ebola epidemic in the region continues to spread, WHO officials are attempting to speed drug development and therapies. But extensive use of the vaccine is still “a pretty long way off,” Fauci told Bloomberg News. “The epidemic is not going to be contained by what we are doing now.”