The first dose of AstraZeneca’s COVID-19 vaccine followed by a second dose of Pfizer’s vaccine increase the immunity manifold, an Oxford University study has found.
According to the study, mixed doses of AstraZeneca and Pfizer administered 8 weeks apart produced 4 times greater immunity than two doses of AstraZeneca or two doses of Pfizer.
Professor Matthew Snape, Oxford University Professor and Chief Investigator of the study, has said that “the study aimed to evaluate up to what extent mixed doses of AstraZeneca and Pfizer vaccines can be used interchangeably.”
He added that mixing doses will also provide healthcare authorities greater flexibility for booster programs in countries that are in advanced vaccination stages, while also supporting countries that are in early vaccination stages or facing supply challenges.
The study supports the decision of some EU countries that have started administering alternatives to AstraZeneca as the second dose after the vaccine was linked with rare and fatal blood clots in the brain.
For instance, Spain and Germany are administering mRNA-based vaccines of Pfizer or Moderna as second doses in young adults who have already received the first dose of AstraZeneca’s vaccine.