India may be planning to study a regimen of mixing of different coronavirus vaccine doses to ascertain its efficacy in enhancing the immune response, ANI reported on Monday, quoting the chief of a Covid-19 Working Group.

Dr NK Arora, the chairperson of Working Group of the National Technical Advisory Group on Immunisation, said that similar studies were being conducted in Spain and the United Kingdom using AstraZeneca’s Covishield and Pfizer vaccine doses administered on alternate days.

A study published in medical journal, The Lancet, had showed that people who were given the AstraZeneca vaccine as the first dose and Pfizer’s as the second reported more short-lived side effects. The study, however, did not say if the mixing of vaccines could help protect against the infection.

Another study in Spain found that the two vaccines given in the same order was highly effective. One of the scientists said that 1.7% of participants reported severe side effects such as headaches and muscle pain.

Arora explained that the two vaccines may be given in different orders for three reasons. “One is that these become convenient programmatically, but more importantly, it shouldn’t create any safety issues and the third is to ascertain if there is an immune advantage, whether the effectiveness of this mix and matching increases the protective efficacy of the vaccines,” he said. “So, all these three things have to be taken care of simultaneously.”

Citing an incident in which different vaccine doses were administered to beneficiaries, Arora clarified that there were no safety concerns but said that it should not have happened.

Earlier in the month, 20 villagers in Uttar Pradesh’s Siddharthnagar district were administered one dose of Covishield and a second dose of Covaxin during vaccinations against Covid-19. On May 27, Dr VK Paul, the chairperson of the National Expert Group on Vaccine Administration for Covid-19, had said that the vaccine mix up was unlikely to have any significant adverse effects. Paul had also said that the Centre was planning to mix-and-match vaccine doses on a trial basis.

India has so far administered 21,15,70,198 Covid-19 vaccine doses, with 4,33,67,727 beneficiaries getting both shots, government data showed.

On Monday morning, India’s Covid-19 case count reached 2,80,47,534 with 1,52,734 new infections recorded in 24 hours. As many as 3,128 fatalities pushed the toll to 3,29,100. There are 20,26,092 active Covid-19 cases and as many as 2,56,92,342 have recovered.

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