Oxford University and AstraZeneca became the first Covid-19 vaccine manufacturers to publish the results of clinical trials in a scientific journal on Tuesday, removing a major obstacle in the global race to produce safe and effective drugs for the new coronavirus.
The study, published in the respected medical journal Lancet, confirmed that the vaccine works in an average of 70 percent of cases.
It comes during a stream of positive developments that has raised hopes that the rollout of vaccines could help curb a pandemic that has killed more than 1.5 million people and affected communities worldwide.
On Tuesday, Britain became the first country in the Western world to start vaccinations with a rival vaccine developed by Pfizer-BioNTech after approving it for public use last week.
Andrew Pollard, director of the Oxford Vaccine Group, said the publication in the Lancet showed that developers “shared data in a transparent way”.
He said a series of vaccines would be needed to get the pandemic on its heels, “otherwise we will still be in this position in six months”.
“This really can not be a competition between developers, this must compete against the virus,” he told a press briefing.
The vaccine protects against symptomatic disease in 70% of cases – with a vaccine efficacy of 62% for those receiving two full doses and 90% for those receiving half and then a full dose. (2/6) pic.twitter.com/RIXPmWE0l3
– The Lancet (@TheLancet) December 8, 2020
The study showed that the vaccine had an effect of 62 percent for those who received two full doses and 90 percent for those who received a half and a full dose.
AstraZeneca and Oxford were asked last month about their analysis – which looks at data from a total of 23,000 people in separate trials with different protocols – after releasing an overview of the results.
These were targeted at the smaller group who received an initial half dose due to a mistake.
Tuesday’s study confirmed that this group of 1367 participants did not include adults over 55 years of age.
The authors said they provided additional analysis to Lancet peer reviewers who suggested that improved results for the half-dose group were not due to other factors such as age.
But they said more research was needed.
AstraZeneca said it would be up to regulators to decide on the basis of whether people would receive two full doses or half a dose followed by a full dose.
“I think it’s fair to say that more research is needed to explain the exciting outcome,” Pollard said.
He confirmed that the use of a lower initial dose was “unplanned” and the result of a measurement deviation, but once researchers realized this, it was incorporated into the trial with the approval of regulators.
The results are likely to present a “dilemma” to regulators, says Simon Clarke, associate professor of cellular microbiology at the University of Reading.
He said that while the half-dose regimen showed better protection against disease and also to reduce asymptomatic transmission, the group was “relatively small”.
“In addition, it did not contain any older participants (55 years or older) and it is still possible that if the regulators allowed the vaccine to be used in this way, the most risky group may not be protected.”
In total, the authors analyzed data from Phase 3 – end – stage clinical trials in the UK and Brazil, involving 11,636 people, together with safety data from a total of 23,745 study participants in the UK, Brazil and South Africa.
There were 131 cases of symptomatic COVID-19 disease more than 14 days after the second dose of vaccine in these 11,636 people – 30 of them belong to the group that received a vaccine with either dose and 101 were in the control group.
The study said no hospital stays or serious illnesses had been reported in the Covid-19 vaccine group to date.