Scientists at Oxford University say their experimental coronavirus vaccine prompted a protective immune response in hundreds of people who got the shot in early trials.
The vaccine, called AZD1222 and being developed by AstraZeneca and scientists at the United Kingdom’s University of Oxford, did not lead to any serious side effects, and elicited antibody and T-cell immune responses, according to trial results published in The Lancet medical journal on Monday.
In the research, scientists said they found their experimental COVID-19 vaccine produced a dual immune response in people aged 18 to 55 that lasted at least two months after they were immunised.
“We are seeing good immune response in almost everybody,” said Dr Adrian Hill, director of the Jenner Institute at Oxford University.
“What this vaccine does particularly well is trigger both arms of the immune system,” he said.
Hill said neutralising antibodies are produced – molecules that are key to blocking infection.
He said larger trials evaluating the vaccine’s effectiveness, involving about 10,000 people in the UK as well as participants in South Africa and Brazil are still under way. Another big trial is slated to start in the US soon, aiming to enrol about 30,000 people.
Head of emergencies at the World Health Organization praised the “good news” from the results shown in early trials, but warned “there’s a long way to go”.
“We now need to move into larger-scale real-world trials,” Dr Michael Ryan told reporters at a news conference in Geneva. “But it is good to see more data and more products moving into this very important phase of vaccine discovery.”
UK Prime Minister Boris Johnson, whose government has helped to fund the project, hailed the results as “very positive news”.
Wafaa el-Sadr, professor of epidemiology and medicine at Columbia University, told Al Jazeera a timeline of six months will likely determine if the vaccine is safe and effective for mass production.
“I think in all likelihood we’re looking at six months. I do think the development of these vaccines for COVID-19 has been moving at an accelerated pace… At the same time, there is movement for the manufacture of these vaccines in the hope that if the data do show success – meaning safe and effective – that we will have already the manufacturing capacity in place at that point,” said el-Sadr.
But, she added: “I do think it’s important to stress again that we cannot let our guard down. We don’t have a vaccine in hand. We don’t have a safe and efficacious vaccine yet, and for the foreseeable future we have to be careful to adhere to the public health measures that we know can prevent transmission of this virus.”
Al Jazeera’s Paul Brennan, reporting from Oxford city, said the progress looks hopeful but there are no guarantees at this stage.
“The ideal vaccine needs to be effective after one or two doses, it must be good for elderly people and target participants such as people with existing health conditions. It also needs to be effective for a period of longer than six months and at this stage its too early to say whether or not this vaccine actually meets those criteria,” he said.
How quickly scientists are able to determine the vaccine’s effectiveness will depend largely on how much more transmission there is, but Hill estimated they might have sufficient data by the end of the year to decide if the vaccine should be adopted for mass vaccination campaigns.
Hill said Oxford has partnered with drugmaker AstraZeneca to produce their vaccine globally, and that the company has already committed to making two billion doses.
“There was a hope that if we had a vaccine quickly enough, we could put out the pandemic,” Hill said, noting the continuing surge of infections globally.
“I think it’s going to be very difficult to control this pandemic without a vaccine.”
AstraZeneca’s is among the leading vaccine candidates against a pandemic that has killed more than 600,000, alongside others in mid- and late-stage trials.
AstraZeneca has signed agreements with governments around the world to supply the vaccine should it prove effective and gain regulatory approval.
The company has said it will not seek to profit from the vaccine during the pandemic.