Covid: UK trial examining mixing different coronavirus vaccines calls for volunteers

  • Video report by ITV News Health Editor Emily Morgan

A UK trial looking at whether different Covid-19 vaccines can be safely mixed is calling for volunteers.

The scientist leading the trial, dubbed Com-Cov, said he is looking for people aged 50 and over to take part in the government-backed study to determine whether different coronavirus vaccines can safely be used for the first and second doses.

Currently, people receive one dose of either the Pfizer/BioNTech or Oxford/AstraZeneca vaccine and then their second dose 12 weeks later.

The programme, which has received £7 million in funding from the government’s Vaccine Taskforce, aims to establish whether a mixed-dose vaccine regimen is better than, or a good alternative to, using two doses of the same coronavirus jab.

  • ITV News Health Editor Emily Morgan explains how the UK could be in a much better position by the end of March in terms of vaccinations if it continues as it is doing now

Speaking on Sky News, Chief investigator in the Com-Cov study, Professor Matthew Snape said those with underlying health conditions such as diabetes or heart disease will be able to take part in the trial because "we are trying to get a population that is representative of the UK". He said the study will look at whether mixing doses of the Oxford University/AstraZeneca and Pfizer/BioNTech vaccines is as good as using two doses of the same Covid-19 jab. "We are looking to see if the immune response that generates is as good as the currently approved schedules," he said.

Vaccines Deployment minister Nadhim Zahawi welcomed the study, which could make the vaccine rollout "more efficient".

He stressed that it would not impact the current deployment of jabs.

"If you've had a Pfizer vaccine, you'll get your second dose within 12 weeks of Pfizer; if you had Oxford/AstraZeneca, you'll get your Oxford vaccine within 12 weeks," he toldBen Shephard and Susanna Reid on ITV's Good Morning Britain."

"The UK remains at the forefront of Covid vaccine and, of course, research overall," Mr Zahawi said.

"This (study) is look at how we can develop, be even more efficient for the UK, but also for the rest of the world.

"Because the one thing to remember, is that we will not be safe, even, as I will absolutely will do, deliver that mid-February target for the most vulnerable four cohorts, and then keep going for the nine cohorts in phase one, and then keep going beyond that until each adult is vaccinated, we still have to make sure the rest of the world is also vaccinated.

"And this research will help us understand how we can use vaccines more efficiently."

The launch comes after England’s chief medical officer Professor Chris Whitty warned the pace of the vaccine rollout will inevitably slow as more people get their second jab.

At a coronavirus update from Downing Street on Wednesday, he said suggestions all adults in the UK could get their first dose by the end of May and the second by the end of August were “very optimistic”.

Boris Johnson has hailed the “colossal” effort by health workers in getting a first jab to more than 10 million people – almost a fifth of the adult population – across the four nations.

(PA Graphics) Credit: PA Graphics

However, England’s deputy chief medical officer Professor Jonathan Van-Tam, who is the senior responsible officer for the new study, said that being able to mix vaccines would give them greater flexibility in future.

“Given the inevitable challenges of immunising large numbers of the population against Covid-19 and potential global supply constraints, there are definite advantages to having data that could support a more flexible immunisation programme, if needed and if approved by the medicines regulator,” he said.

“It is also even possible that by combining vaccines, the immune response could be enhanced giving even higher antibody levels that last longer; unless this is evaluated in a clinical trial we just won’t know.”

Professor Jonathan Van-Tam has said mixing vaccines could give better immunity. Credit: PA

The study, dubbed Com-Cov, run by the National Immunisation Schedule Evaluation Consortium (NISEC), will involve more than 800 volunteers over the age of 50 in England.

Some will receive the Oxford-AstraZeneca jab followed by the Pfizer-BioNTech vaccine or vice versa - four or 12 weeks apart.

More vaccines will be added to the list as they get approved for use in the UK.

Initial results are expected to become available during the summer – in time to inform policy on the use of booster vaccines among younger age groups.

Vaccines minister Nadhim Zahawi hailed the trial as "hugely important" adding that it "will provide us with more vital evidence on the safety of these vaccines when used in different ways.

“Nothing will be approved for use more widely than the study, or as part of our vaccine deployment programme, until researchers and the regulator are absolutely confident the approach is safe and effective.”

At Wednesday’s news conference, Prof Whitty said the UK was “past the peak” of the current wave of the pandemic and that cases should continue on a “downward slope” as long as people continued to follow the rules on social-distancing.

Mr Johnson, however, has continued to resist calls from some Tory MPs to bring forward the planned re-opening of schools in England from March 8.

The prime minister said it was three weeks after the date when the most vulnerable groups – including all over 70s – should have received their first jab, giving time for immunity to kick in.

Boris Johnson is resisting pressure to bring forward the re-opening of schools in England. Credit: PA

In Scotland, First Minister Nicola Sturgeon has said schools will begin a phased reopening from February 22 while the Welsh Government is due to make a decision by the end of the week on whether to reopen schools after the February half-term.

However, the prime minister said infection levels remained “forbiddingly high” and they did not want to be “forced into reverse”.

In the 24 hours to 9am on Wednesday, a further 1,322 people died within 28 days of a positive Covid test, while a further 19,202 new coronavirus cases were recorded

“We think this is the prudent and cautious approach. I think it is much better to stick to that,” he said.

Mr Johnson also said that Health Secretary Matt Hancock would be setting out further details on Thursday of the government’s plans for quarantine hotels for travellers arriving in England.

Downing Street later made clear that no announcements on borders would be planned for the day.

Ministers have been under fire for failing to come forward with details as to when the scheme will come into effect, a week after it was first announced.

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