The 2014 Ebola virus outbreak
in western Africa—and the media-fueled global panic that ensued—highlighted the need for a viable vaccine against the disease.
Now, research suggests such a vaccine may be in the pipeline; arguably welcome news in light of the recent 2017 Ebola outbreak
in the Democratic Republic of Congo.
In a Phase 1B study
published June 9, 2017 in the journal Lancet Infectious Diseases
, researchers found that the novel vaccine, called rVSVΔG-ZEBOV-GP or V920 for now, was well-tolerated and “stimulated a rapid onset of binding and neutralizing antibodies,” which persisted for up to 1 year, when administered at a dose of 2 × 10⁷ PFU dose. V920 is a live attenuated recombinant vaccine in which the vesicular stomatitis virus envelope glycoprotein is replaced by the envelope glycoprotein of the Kikwit strain of the Zaire Ebola virus. It was originally developed in the National Microbiology Laboratory of the Public Health Authority of Canada.
“[These] results… strengthen the interim estimates and conclusions made earlier that the V920 vaccine has high protective efficacy and eﬀectiveness to prevent Ebola virus disease,” study coauthor Beth-Ann Coller, PhD, Vaccine Development Team Leader at Merck, told Contagion®
. “We believe that safe and effective Ebola vaccines will be critical to a comprehensive Ebola prevention and control program as well as to containing future outbreaks.”
For the Phase IB study, the authors enrolled and randomly assigned 513 healthy adults to 1 of 2 cohorts at 8 US-based study sites to receive a single IM injection of V920 or placebo, at 1 of 4 doses (3 × 10³ PFU, 3 × 10⁴ PFU, 3 × 10⁵ PFU, or 3 × 10⁶ PFU in cohort 1 and 3 × 10⁶ PFU, 9 × 10⁶ PFU, 2 × 10⁷ PFU, or 1 × 10⁸ PFU in cohort 2). In cohort 1, 256 participants received the vaccine and 74 received placebo, while in cohort 2, 162 participants received the vaccine and 20 received placebo (1 participant did not receive the vaccine or placebo due to unsuccessful phlebotomy).
At the recommended 2 × 10⁷ PFU dose, the most common local adverse events within the first 14 days following vaccination were arm pain and injection-site tenderness. The most common systemic adverse events were headache, fatigue, myalgia, subjective fever, shivering or chills, sweats, joint aches and pain, objective fever, and joint tenderness or swelling. Postvaccination arthritis and dermatitis, both common adverse events cited in earlier trials, occurred in 4.5% and 5.7%, respectively, of those who received V920, versus 3.2% and 3.2%, respectively, of controls.