CHANDAN KHANNA/AFP via Getty Images
A large trial of a coronavirus vaccine developed by the University of Oxford has begun in the US. With similar trials already under way in the UK and Brazil, hopes are rising that we could find out if the vaccine works before the end of the year.
A collaboration between the Oxford team and the drug firm AstraZeneca, this vaccine is one of the front-runners. Worldwide, eight other coronavirus vaccines have started large-scale trials, and 24 have begun smaller trials to assess safety.
On 31 August, the US National Institutes of Health announced that the first of 30,000 volunteers had received either the Oxford vaccine, known as AZD1222,
or a placebo consisting of salty water.
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One in three volunteers will get the placebo, but the trial is double blind, meaning that neither the researchers nor the volunteers know which is being administered. The trial is being carried out at 80 sites across the US.
In the UK, nearly 10,000 volunteers have already been given either AZD1222 or a placebo.
Once a certain number of the volunteers in these trials test positive for covid-19, researchers will be allowed to unblind the data and look to see if there are fewer – or even no – cases in those given the vaccine.
It could take some time to get to this point in the UK, as the number of daily coronavirus cases remains low post-lockdown, although the numbers are slowly increasing.
The trials in Brazil and the US might yield results sooner, as these countries have more confirmed cases per capita.
Once the results of large trials are in, regulators will consider whether to approve any vaccine. The director of the Oxford vaccine group, Andrew Pollard, told the BBC last week that the team might be able to put results before regulators this year.
Last week, the UK government announced that it is considering changing the law to allow it to grant temporary approval to any vaccine from October.
Some are concerned that intense political pressure could lead to vaccines being approved prematurely, before we are certain they are safe and effective enough.
Governments have signed deals to buy hundreds of millions of doses of the various vaccines being developed if they are successful, and as trials progress, capacity for manufacturing is being ramped up.
On 1 September, for instance, biotech company Oxford Biomedica announced that it had expanded an agreement with AstraZeneca to produce 10 times as much of the Oxford vaccine as previously agreed. “We will be producing tens of millions of doses once fully up and running,” says an Oxford Biomedica spokesperson.
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