A new two-vaccine regimen for Ebola may offer protection against the deadly disease for about one year, according to the results of an early human trial.
The Ebola regimen, including Ad26.ZEBOV and MVA-BN-Filo vaccines, induced an immune response that persisted for about one year in healthy adult volunteers, researchers said.
Both of the vaccines in the regimen use harmless viral vectors, or carriers, to deliver proteins of the Ebola virus, which prompt an immune response.
Ad26.ZEBOV uses a modified adenovirus vector to express proteins from Zaire ebolavirus, which was the species responsible for the 2014-2015 outbreak in West Africa.
MVA-BN-Filo uses a modified vaccinia virus Ankara vector to express proteins from various species of Ebola virus, as well as the related Marburg virus.
The Phase 1 trial enrolled healthy participants ages 18-50 years in the UK and was conducted by the Oxford Vaccine Group at the University of Oxford.
Participants were selected randomly to receive either the two-vaccine regimen or placebo (saltwater injections).
Previously reported initial results showed the two-vaccine regimen is safe, well-tolerated and induced immune responses in participants eight months after immunisation.
Of the 75 participants who received the vaccine regimen, 64 remained in the study for a follow-up visit on day 360.
No serious vaccine-associated adverse events were observed, and all 64 participants maintained antibodies to Ebola virus at day 360, researchers said.
They noted that additional research is necessary to assess the durability of immunity beyond one year and the immune response to booster doses of vaccine.
The study was published in the Journal of the American Medical Association.