We’ve heard that COVID-19 vaccines are not mixed and matched and that both doses are needed from the same vaccine.
But a study is underway in the United Kingdom to see if that might be possible or even preferable.
The reason vaccines are not mixed and matched is because they were not studied that way. So we are unsure if they would still produce the same high efficacy and safety.
But there are good reasons to find out if they could be used interchangeably for the initial two doses and even for boosters down the road.
Oxford University researchers are conducting the clinical trial that began by looking at the immune responses of trial participants given first the AstraZeneca vaccine and then the Pfizer shot, or the other way around.
The trial is now expanding to include the Moderna and Novavax vaccines too. If it was possible, mixing and matching could help ease vaccine supply shortages and speed up vaccination programs.