Mixing and matching the coronavirus vaccines made by Pfizer-BioNTech and AstraZeneca-Oxford generates a “robust immune response” against the virus, according to a study led by Oxford University.
The Com-COV study, funded by the UK government, is looking into the feasibility of using a different vaccine for the initial “prime” vaccination to the follow-up “booster” vaccination.
It found that alternating doses of the two vaccines generated strong immunity. Doses of the vaccines were given four weeks apart with data for a 12-week dose interval due soon, the researchers said after publishing their latest findings in the reputed UK medical journal Lancet preprint server on Monday.
“Both mixed schedules (Pfizer-BioNTech followed by Oxford-AstraZeneca, and Oxford-AstraZeneca followed by Pfizer-BioNTech) induced high concentrations of antibodies against the SARS-CoV2 spike IgG protein when doses were administered four weeks apart,” the researchers observed.
“This means all possible vaccination schedules involving the Oxford-AstraZeneca and Pfizer-BioNTech vaccines could potentially be used against Covid-19.”
The findings could add much-needed flexibility to vaccination programs around the world, according to Matthew Snape, associate professor in paediatrics and vaccinology at the University of Oxford, and chief investigator on the trial.
"The Com-COV study has evaluated 'mix and match' combinations of the Oxford and Pfizer vaccines to see to what extent these vaccines can be used interchangeably, potentially allowing flexibility in the UK and global vaccine roll-out," said Professor Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator on the trial.
Professor Snape said these results are an invaluable guide to the use of mixed dose schedules, but the interval of four weeks studied here is shorter than the eight to 12-week schedule most commonly used for the Oxford-AstraZeneca vaccine.