Researchers Studying What Happens When You Mix & Match COVID Vaccines

The results of this trial may help show whether it’d be better off switching up vaccines next time around. Read more:

Video Transcript

- A new study in the UK is trying to determine what happens when different types of vaccines are deliberately mixed up.

- Researchers hope the results could help relive-- relieve, rather, global vaccine shortages and protect against variants. CBS4's Charlie D'Agata reports from Oxford University.

CHARLIE D'AGATA: Reeka Trikha has no idea what's about to be injected into her body.


CHARLIE D'AGATA: Not at all?

REEKA TRIKHA: No, I leave it in the capable hands of the doctors.

CHARLIE D'AGATA: A blind leap of faith, not just testing one vaccine, but deliberately mixing them up to see what happens. More than 800 volunteers age 50 and above taking part in the Oxford University-led trial, some given a Pfizer prime shot followed by an AstraZeneca booster or AstraZeneca followed by Pfizer, others the same vaccine twice, the standard way, for comparison, shots separated by 4 and 12 week gaps to see which works best. Professor Paul Heath is principal investigator at one of the eight trial sites across the UK.

PAUL HEATH: With that knowledge, then we can have complete confidence that a number of different vaccines can be rolled out and implemented in a population very quickly, very efficiently, without any concern about inadvertent mixing of the combination.

CHARLIE D'AGATA: You're talking about potentially increasing flexibility, capacity.


- Not just the Pfizer or AstraZeneca vaccine, but potentially any combination of any COVID vaccine, easing inevitable supply issues around the globe. Not only that, Professor Heath says alternating vaccines could even produce better overall protection against emerging variants.

PAUL HEATH: Potentially with a prime boost of different vaccines, the broader response, the broader immune response that ensues will be sufficient to deal with, for example, the South African variant.

CHARLIE D'AGATA: For those who have already had a vaccine, it's unclear just how long the protection lasts. If we all need a booster, the results of this trial may help show whether we'd be better off switching up vaccines next time around. Charlie D'Agata, CBS News, Oxford University, England.