New monkey studies show that one shot of an experimental Ebola vaccine can trigger fast protection, but the effect waned unless the animals got a booster shot made a different way, Reuters reported.
Human trials are set to begin at the National Institutes of Health for the first human safety study of this vaccine in hopes it eventually might be used in the Ebola outbreak in West Africa, according to Reuters.
The NIH published some of the key animal research behind those injections on Sunday, Reuters reported.
The vaccine was deemed promising because a single dose protected all four vaccinated monkeys when they were exposed to high levels of Ebola virus just five weeks later, researchers reported in the journal Nature Medicine, according to Reuters.
Researchers exposed monkeys to Ebola 10 months after vaccination, and this time only half were protected, Reuters reported.
The researchers tried simply giving another dose as a booster two months later, but that didn't work well enough, so they tried a different approach called "prime-boost," according to Reuters.
The first dose, to prime the immune system, was that original chimp virus-based Ebola vaccine, but for the booster two months later, researchers made the vaccine a different way and encased the same Ebola gene pieces inside a poxvirus that's used to make a vaccine against smallpox, Reuters reported. This time, all four monkeys still were protected 10 months after the initial shot.
The vaccine is made with a chimpanzee cold virus, used as a delivery system for pieces of an Ebola gene, according to Reuters.
The World Health Organization said Friday that it would try to speed the use of certain experimental products, including two vaccine candidates, as the Ebola outbreak worsens, Reuters reported.
WHO said it expects early results from first-stage studies to see if the vaccine appears safe and triggers an immune reaction in people by November, according to Reuters.
