Oxford University’s experimental coronavirus vaccine is safe and generated a strong immune response in the people who volunteered to help trial it, researchers have said, raising hopes it could contribute to ending the pandemic.
Professor Sarah Gilbert, from Oxford’s Jenner Institute, said they were more than happy with the first results, which showed good immunity after a single dose of vaccine. “We’re really pleased that it seems behaving just as we thought it would do. We have quite a lot of experience of using this technology to make other vaccines, so we knew what we expected to see, and that’s what we have seen,” she told the Guardian.
The results published in the Lancet medical journal are preliminary, with the effect of the vaccine measured by the amount of antibodies and T-cells it generates in the blood of the volunteers – not in any response to the virus itself.
Large-scale trials have begun in Brazil and South Africa, however, where infection rates are still high and it will be possible to assess whether vaccinated individuals are less likely to get COVID-19 than others.
The results were “a really important milestone” on the path to a vaccine, said the study’s lead author, Professor Andrew Pollard. They showed that the vaccine was very well tolerated by more than 1,000 volunteers. “We are seeing exactly the sort of immune responses we were hoping for, including neutralising antibodies and T-cell responses, which, at least from what we’ve seen in the animal studies seem to be those that are associated with protection.”
The problem is, he said, “we just don’t know what level is needed if you meet this virus in the wild, to provide protection, so we need to do the clinical trials and to work that out.”
Hopefully they would find out from the trials to come, which would help all vaccine developers.
“We don’t know what high is. We’ve got immune responses that we can measure we can see the virus being neutralised when the antibodies are tested in the laboratory, but we don’t know how much is needed. I mean it’s encouraging but it’s only the first milestone on this this long path,” he said.
Ideally the vaccine would protect against any infection, but scientists already accept it may reduce the severity of the disease instead, meaning people would be less likely to become very sick and die.
The volunteers have been followed up for eight weeks so far after immunisation.A further question is how long any immune response will last – if for only six months or a year, people might need regular booster shots.
There are also big questions over whether it will work in older adults – flu vaccinations do not give as much protection to older people, whose immune systems function less well than younger people’s. The trial participants were between 18 and 55 years old. The risk of dying from COVID-19 rises dramatically with age from about 65. Trials are now being undertaken in an older age group.
The Oxford vaccine is delivered by a weakened chimp adeno virus
“The immune system has two ways of finding and attacking pathogens – antibody and T-cell responses. This vaccine is intended to induce both, so it can attack the virus when it’s circulating in the body, as well as attacking infected cells,” said Pollard.
“We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period. However, we need more research before we can confirm the vaccine effectively protects against Sars-CoV-2 infection, and for how long any protection lasts.”
Health secretary Matt Hancock said: “A safe and effective vaccine is our best hope of defeating coronavirus and returning to life as normal.
“We have some of our best scientists and researchers working on this, but members of the public have a vital role to play too. So I urge everyone who can to back the national effort and sign up to the NHS COVID-19 vaccine research registry to help find a vaccine as soon as possible.
“Every volunteer will be doing their bit towards finding a vaccine for COVID-19 that will have the potential to save millions of lives around the world and bring this pandemic to an end.”
