Notably, in terms of possible vaccine efficacy, antibody responses were observed in most of the study participants by day 14 following administration. Among those who received the 2 × 10⁷ PFU dose, the geometric mean IgG ELISA endpoint titer was 1624, seroconversion was 95.7%, the geometric mean neutralizing antibody titer (via PRNT360) was 250, and seroconversion was, again, 95.7%, with all responses sustained for 1 year.
Some Phase II and III studies of V920 have already been conducted, with results expected soon, and additional trials are underway, including the PREVAC trial under the auspices of the French National Institute of Health and Medical Research, the US National Institute of Allergy and Infectious Diseases, and the London School of Hygiene and Tropical Medicine.
“Our plans call for us to file for licensure as soon as possible,” Dr. Coller said. “In the meantime, we remain poised to distribute vaccine in the context of expanded access clinical trials in response to an Ebola outbreak should an emergency request be made.”
In a commentary
published with the study findings, Elizabeth C. Clarke and Steven B. Bradfute of the Center for Global Health at the University of New Mexico, write that, “The strength of this study lies in its demonstration of the longevity of neutralizing antibody responses after vaccination… Good longevity of immune responses is particularly positive for future development of Ebola virus vaccines, since it could increase the utility of the vaccine for health-care workers and people in endemic regions who are most likely to be exposed to the virus over a prolonged period.”
Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.
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