The Centre on Thursday said that a mix-up of coronavirus vaccine doses was unlikely to cause any significant adverse effects, NDTV reported.

The statement was in response to reports that 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.

Dr VK Paul, the chairperson of the National Expert Group on Vaccine Administration for Covid-19, said that the matter of mixing vaccines should be looked into. “We will have to wait for more scientific understanding... but even if two doses of two different vaccines are given, this should not be a cause of concern,” Paul said.

Sandeep Chaudhary, the chief medical officer of Siddharthnagar district, admitted that it was an oversight and said that he had received a report on the incident. “I have asked for an explanation from those who are guilty,” Chaudhary said. “We will take whatever action is possible.”

Earlier, a 72-year-old man in Maharashtra was also given two different vaccines. Dattatraya Waghmare, a resident of Jalna district, said he got Covaxin on March 22 and Covishield on April 30. His son, Digambar, said that Waghmare suffered from minor side effects such as mild fever, rashes and anxiety attacks.

The impact of mixing vaccines is still a matter of research. On Thursday, Paul also said that the Centre was planning to mix-and-match vaccine doses on a trial basis, reported Business Standard.

On May 22, Paul had told the Hindustan Times that it was scientifically possible. “One shot of one type produces antibodies and the second shot from another will increase that,” he said. “Scientifically, there is no problem.” Paul, however, also added that it needed more research.

A study published in medical journal, The Lancet, 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, according to Bloomberg. 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, reported Reuters, citing the preliminary results. One of the scientists said that 1.7% of participants reported severe side effects such as headaches and muscle pain.

Meanwhile, India on Thursday reported 2,11,298 new cases, taking the overall tally to 2,73,69,093 since the pandemic first broke out in January 2020. The toll rose by 3,847 to 3,15,235, while the active caseload stood at 24,19,907.

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