RAPID AND DURABLE PROTECTION AGAINST EBOLA VIRUS WITH A NEW VACCINE
One shot of an
experimental vaccine made from two Ebola virus gene segments incorporated into
a chimpanzee cold virus vector (called chimp adenovirus type 3 or ChAd3)
protected all four macaque monkeys exposed to high levels of Ebola virus 5
weeks after inoculation, report National Institutes of Health (NIH) scientists
and their collaborators.
The ability of the
ChAd3 Ebola virus vaccine to elicit rapid protection in monkeys is notable as
the world health community battles an ongoing Ebola virus disease outbreak in
West Africa. While the protective effects of the single shot waned over time, two
out of four inoculated animals were protected when challenged with Ebola virus
10 months after vaccination.
The research team,
headed by Nancy J. Sullivan, Ph.D., of the National Institute of Allergy and
Infectious Diseases Vaccine Research Center, also demonstrated increased levels
of durable protection using an additional vaccine. They inoculated four
macaques first with the ChAd3 Ebola vaccine, then 8 weeks later with a booster
vaccine containing Ebola virus gene segments incorporated into a different vector
(a poxvirus).
Ten months after the
initial inoculation, four out of four animals that received both shots were
fully protected from infection with high doses of Ebola virus, demonstrating
that the prime-boost regimen resulted in durable protection.
The research team
included scientists from Okairos, a Swiss-Italian biotechnology company now
part of GlaxoSmithKline, and the U.S. Army Medical Research Institute of
Infectious Diseases. The experimental ChAd3 Ebola vaccine used in these
non-human primate studies is the same one currently being tested in an
early-stage human clinical trial at the NIH in Bethesda, Maryland.
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