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By Julie Steenhuysen
May 14 (Reuters) - A closely watched coronavirus vaccine
being developed by scientists at Oxford University appears
protective in a small study of six monkeys, promising findings
that led to the start of human trials late last month, U.S. and
British researchers reported on Thursday.
The preliminary findings, which have not undergone rigorous
review by other scientists, appeared on the preprint server
bioRxiv on Thursday.
British drugmaker AstraZeneca last month announced
it had teamed up with researchers at the Oxford Vaccine Group
and the Jenner Institute, which are developing the vaccine.
According to the report, some of the monkeys given a single
shot of the vaccine developed antibodies against the virus
within 14 days, and all developed protective antibodies within
28 days, before being exposed to high doses of the virus.
After exposure, the vaccine appeared to prevent damage to
the lungs and kept the virus from making copies of itself there,
but the virus was still actively replicating in the nose.
Stephen Evans, a professor of pharmacoepidemiology at the
London School of Hygiene & Tropical Medicine, said the monkey
data were “very definitely” good news.
“It is one of the hurdles to be passed by the Oxford vaccine
and it has cleared it well,” he said in an emailed comment.
Although success in monkeys is seen as a key step, many
vaccines that protect monkeys in the lab ultimately fail to
protect humans.
Evans said one key finding was particularly reassuring –
that there was no evidence of immune-enhanced disease, in which
instead of protecting against a virus, a vaccine actually makes
the disease worse.
“This was a definite theoretical concern for a vaccine
against SARS-CoV-2 and finding no evidence for it in this study
is very encouraging,” he said.
Last month, British researchers started dosing human
volunteers with the vaccine in a small safety trial, making it
one of only a handful to have reached that milestone. As of May
13, 1,000 people have received the vaccine, the researchers
said.
Other vaccines in human trials include those by Moderna Inc
, Pfizer Inc and BioNTech SE and
China's CanSino Biologics Inc.
Globally, there are more than 100 experimental vaccines
under development to fight the new coronavirus that has so far
infected 4.39 million people and killed 296,847.
A vaccine that protects people from the coronavirus could
end the pandemic, but finding one that works and manufacturing
enough doses is a huge challenge.
Normally, it can take up to 10 years to develop a working
vaccine, but the urgency of the pandemic has resulted in
accelerated timelines, and some officials estimate a working
vaccine could be available for emergency use as early as this
fall.
(Reporting by Julie Steenhuysen; Additional reporting by Kate
Kelland in London; Editing by David Gregorio)
