A trial of mixing and pairing different COVID vaccines could be a game-changer

Oxford, England – While most COVID-19[female[feminine vaccine volunteers in the trial have no idea whether they are getting the real vaccine or a placebo, for volunteers in a potentially breakthrough new study in the UK, there is no placebo. It is not a question of whether they had a chance, but which – or rather both.

As reported by CBS News correspondent Charlie D’Agata, this is the first such COVID-19 vaccine trial, and scientists say the results could revolutionize the future of vaccine distribution while offering the most powerful weapon to date against emerging variants of the coronavirus.

D’Agata met Reeka Trikha as she was about to receive her first injection in the trial. She had no idea what was going to be hit in her arm.

“I’m going to leave it in the competent hands of the doctors,” she said, taking the leap of faith.

Scientists behind the Oxford University trial are very deliberately mixing things up – not just testing one vaccine, but combining doses of two different drugs to see what happens.

More than 800 volunteers aged 50 and over are participating in the trial. Some receive a Pfizer “premium” photo followed by a AstraZeneca As a booster, a second group receives AstraZeneca followed by Pfizer, and a third group of participants receives the same vaccine twice – the standard method – for comparison.

Injections are given at four and twelve week intervals in different test groups to see what works best.

“With this knowledge, we can be completely convinced that a number of different vaccines can be deployed and implemented in a population very quickly, very efficiently, without any concerns about accidental mixing of the combination,” Professor Paul Heath, director of the Vaccine Institute at St. George’s University in London and the principal investigator of one of eight trial sites across the UK, told CBS News.

Evidence from the trial could suggest that not only Pfizer and AstraZeneca vaccines, but potentially any combination of any COVID-19 vaccine could be safe and effective in preventing symptomatic infections. This flexibility could go a long way to alleviating the inevitable supply problems that are already popping up around the world.

But it could be even better news than that: Heath says that using vaccines alternating between an individual’s two doses might actually produce better overall protection against emerging variants of the virus.

“Potentially with a boost from different vaccines, the broader response, the broader immune response that will follow will be enough to deal with, say, the South African variant,” he said, pointing out reference to a strain of the virus which has shown some degree of resistance to currently proposed vaccines.

As unpredictable as the virus has been, two challenges ahead are certain: Global shortages will worsen and the virus will continue to mutate.

The results of the UK trial may offer the best hope for resolving both of these issues.

For those who have already received a vaccine, it is not clear how long the protection will last. If we all end up needing booster shots, research from Oxford will let us know if it’s better to change the vaccine next time.