A coronavirus vaccine being developed by Britain's University of Oxford with pharmaceutical giant AstraZeneca appears to be safe and to produce immunity, researchers said on Monday.
An ongoing trial involving 1,077 healthy adults found that the vaccine "induced strong antibody and T cell immune responses" up to day 56, the researchers wrote in The Lancet medical journal.
They said the immune responses "may be even greater after a second dose," according to a trial with a sub-group of 10 participants.
The British government has already ordered 100 million doses of the potential vaccine, which is among dozens of vaccine candidates worldwide.
"The early stage trial finds that the vaccine is safe, causes few side effects, and induces strong immune responses in both parts of the immune system," the Oxford researchers said.
They said the vaccine produces a cellular immune response, or T cell response, within 14 days of vaccination and an antibody response within 28 days.
The vaccine uses a genetically modified common cold virus that infects chimpanzees, weakened so that it can’t cause disease in humans, said Oxford's Andrew Pollard, the lead author of the study.
"The immune system has two ways of finding and attacking pathogens - antibody and T cell responses," Pollard said.
"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."
"We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period," he said.
More research needed
Pollard cautioned that his team needs "more research before we can confirm the vaccine effectively protects against Sars-CoV-2 infection, and for how long any protection lasts."
Sars-CoV-2 is the scientific name for the coronavirus that causes the respiratory illness Covid-19.
The British government announced earlier on Monday that it has also agreed in principle to buy 90 million doses of vaccines under development by other major pharmaceutical firms based in France, Germany and the United States.
It ordered 60 million doses of a vaccine from French-based Valneva and 30 million of the BNT162 vaccine from a joint programme by German's Biontech and US-based Pfizer.
The deal with Valneva includes an option to buy 40 million extra doses "if the vaccine is proven to be safe, effective and suitable," the government said.
"The hunt to find a vaccine is a truly global endeavour and we are doing everything we can to ensure the British public get access to a safe and effective coronavirus vaccine as soon as possible," Business Secretary Alok Sharma said in a statement.
The reservation of different types of vaccine "will ensure the UK has the best chance possible of securing a vaccine that protects those most at risk," Sharma said.
Thomas Lingelbach, Valneva's chief executive, said his company was "delighted to have been selected to participate in this important programme with the UK government."