A potential coronavirus vaccine being developed by scientists at Oxford University has showed promising signs in a small study of six monkeys.
According to a report, some of the monkeys given a single shot of the vaccine developed antibodies against the virus within 14 days.
All of them developed protective antibodies within 28 days, before being exposed to high doses of the virus, experts said.
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.
The findings, which emerged on Thursday, are only preliminary and have not undergone rigorous review by other scientists.
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.
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.
Prof Evans said it 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.
