Professor Matthew Snape said that alternating stings can cause coronavirus protection
Scientists today said coronavirus vaccines manufactured by Moderna and Novavax would be added to a mix-and-match trial.
The British medical regulator currently requires everyone to have two doses of the same drug – either AstraZeneca, Pfizer or Moderna.
But Oxford University experts are testing whether alternative second doses could trigger a stronger immune response.
Their trial – which could have revolutionized Britain’s revolution – has already assessed the consequences of the combination of AstraZeneca and Pfizer doses.
Another 1,000 volunteers will now be recruited after the study to test combinations, including vaccines made by Moderna and Novavax.
Experts believe that mixing jabs is unlikely to pose any safety issues and predict that it could lead to shots being even more effective in preventing an infection with the virus.
In the wake of AstraZeneca’s fear of blood clots, France has approved giving recipients an alternative second dose. Germany did the same under the 60s.
But until evidence is gathered, they can not say with certainty whether it works and whether it is safe.
Britain only recommended that younger than 30 be offered an alternative and that everyone who has already had their first dose come to their second place unless they are experiencing the extremely rare complication.
Oxford’s mix-and-match trial was first launched in February to investigate whether alternative doses of the Pfizer and AstraZeneca vaccines increase efficacy.
Volunteers must be 50 years of age or older and have received one dose of the Pfizer or AstraZeneca vaccine. Some will be offered the Moderna or Novavax jabs as a second dose, but others will still receive the same dose the second time
The study will be the first to show whether it is possible to mix doses of the Covid vaccine
The Com-COV trials, or the comparison of vaccine vaccination combinations, are the first in the world to look at mixing coronavirus jabs.
It already involves 800 participants, which ranged from the vaccinations of AstraZeneca and Pfizer.
But the new trial will recruit another 175 volunteers in each of the six arms, bringing the total number of volunteers to nearly 2,000.
Participants will be randomly assigned a Moderna or Novavax jab – which will be rubber-stamped by regulators in the coming weeks – as a second dose, eight weeks after receiving the AstraZeneca or Pfizer vaccine.
Some participants will receive the same jab as the first time to set up a ‘check’ for the study, to indicate whether the alternating doses made jabs stronger.
Results will also be compared with the efficacy figures for each stitch from large-scale clinical trials.
Experts will be recruiting volunteers from Monday, but the final results are not expected until early next month, and possibly only in July.
Their findings will be submitted to the Joint Committee on Vaccination and Immunization (JCVI), which will decide whether to allow alternative doses.
The group of top scientists was also responsible for designing the priority list for jabs, and the decision to widen the gap between jabs to 12 weeks to protect as many people as quickly as possible.
The study will not include the Johnson and Johnson jab, which is expected to be approved within days, as it requires only one dose.
Professor Matthew Snape, who is leading the study, said it could offer ministers an alternative if there is a problem with blood clots, or any problems there are.
“The reason we are doing this study is because we do not know what the effect of mixing is,” he said in a press release.
‘The risk of mixing is that you will see suboptimal immune responses, or a reaction that is not as good as in the original vaccine course.
“I would be personally surprised if that were the case, we just do not know what the outcome will be.”
He said mixing jabs could lead to more participants being immune to virus infections compared to current jabs, as it could supplement the body to attack the whole virus rather than just the vein protein – which it uses to invade cells.
Studies have suggested that the South African and Brazilian variants may partially evade immunity because they have deformed nails to which antibodies struggle to bind.
But if the immune system were to attack the whole virus, these changes would not help the virus to slip in unnoticed and cause an infection.
Experts believe that the current harvest of jabs protects against the virus, because antibodies are not the only part of the immune system.
The AstraZeneca vaccine was 76 percent effective in blocking symptomatic Covid infections in clinical trials, compared with 92 percent for Moderna and 95 percent for Pfizer.
But experts point out that these results are ‘very good’ for any vaccine, and the World Health Organization added that the standard is only 50 percent and that annual flu shots are often only about 40 percent effective.
The AstraZeneca and Novavax vaccine uses a cold-modified virus containing Covid vein proteins to teach the immune system how to fight the disease.
While Pfizer and Moderna’s jab use mRNA – instructions for building proteins – to cause the production of the particle particle.
This comes after more than 800 people entered trials to find out if it is possible to mix and match ‘AstraZeneca’ and ‘Pfizer jabs’.
All participants are over 50 and have been stabbed in eight places in England, including London, Birmingham and Liverpool.
The study lasts 13 months, and patients are recruited in February.