A study conducted in the United Kingdom has suggested that mixing COVID-19 vaccines, using shots from different companies for first and second doses, can provide good protection against the SARS-CoV-2 virus.

The Com-Cov trial assessed the efficacy of either two doses of the Pfizer vaccine, two doses of the AstraZeneca vaccine, or one of them followed by the other. All combinations were shown to work well and primed the immune system. The study’s findings also point to the possibility that people who have been given two doses of the AstraZeneca vaccine could have a stronger immune response if given a different vaccine as a booster, if advocated in the autumn… (BBC, June 28, 2021)