Using different vaccine shots for the first and second dose gives good protection against coronavirus, says a study. Results of two doses of AstraZeneca, two doses of Pfizer, or one of them followed by the other, were checked. All combinations showed good results, activating the immune system. Experts say that this test showing good results could offer more flexibility in the vaccine rollout.

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The trials were conducted by the Oxford Vaccine Group’s Com-Cov that looked at the efficacy of combinations of vaccine shots. The trial results also suggested that people who have already received two doses could have had a stronger immune response if they were given a different shot in their second dose. 

Jonathan Van-Tam, the deputy chief medical officer of the UK, said that there was no reason to change the current system in the country of providing the same vaccine shots over the two doses. He also added that it was something that can be looked at for the future. “Mixing doses could provide us with even greater flexibility for a booster programme, while also supporting countries who have further to go with their vaccine rollouts, and who may be experiencing supply difficulties”, said Van-Tam, reported the BBC.

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Countries such as Germany and Spain have already begun mixing doses, offering the Moderna or Pfizer mRNA COVID-19 vaccines as a second dose to younger people who received a shot of AstraZeneca as their first dose. 

The Com-Cov study looked at giving the two doses four weeks apart to 850 volunteers, aged 50 and above.