WASHINGTON United States (Xinhua) --
A two-vaccine regimen intended to protect against
the deadly Ebola virus induced a durable immune response in 100
percent of healthy adult volunteers one year after vaccination,
results from a phase one clinical trial showed Tuesday.
Ebola virus disease
is a severe, often fatal illness in humans. The virus is
transmitted to people from wild animals and spreads in the human
population through human-to-human transmission.
The new study,
published in the Journal of the American Medical Association,
involved two vaccine candidates, one used to stimulate or
“prime” an initial immune response, and a second used to boost
the body’s response.
The trial was
conducted by researchers at the University of Oxford, who
enrolled healthy participants aged 18 to 50 in the United
selected randomly to receive either the two-vaccine regimen or
Of the 75
participants who received the vaccine regimen, 64 remained in
the study for a follow-up visit on day 360.
vaccine-associated adverse events were observed, and all of the
active vaccine recipients maintained antibodies to Ebola virus
at day 360.
This is “the longest
duration follow-up for any heterologous primary and booster
Ebola vaccine schedule to our knowledge,” the researchers wrote
in their paper.
They added that the
two-vaccine strategy “may offer advantages over reactive use of
single-dose vaccine regimens” in at-risk populations, where
durability of immune response is likely to be of primary
Johnson & Johnson,
which developed the prime vaccine, said in a statement that a
total of 10 clinical studies for the Ebola vaccine regimen are
currently being conducted on a parallel track across the U.S.,
Europe and Africa.
company said it, in partnership with Bavarian Nordic, which
developed the booster vaccine, rapidly scaled up production of
the vaccine regimen and now has approximately 1,8 million
regimens available, with the capacity to produce several million
regimens if needed.
investigational prime-boost vaccine regimen, rVSV-EBOV, an
experimental Ebola vaccine developed by the Public Health Agency
of Canada, has already proven highly effective against the
deadly virus during a major trial in Guinea, the World Health
Organization said last year.