The Covaxin shot developed by Bharat Biotech will be used in an emergency situation or as a backup, once the immunisation process against coronavirus begins in the country, All India Institute of Medical Sciences Director Dr Randeep Guleria told ANI on Sunday.

“In an emergency situation when there is a sudden increase in cases and we need to vaccinate, Bharat Biotech vaccine will be used,” he said. “It can also be used as a back-up when we’re not sure how efficacious the Serum Institute vaccine is going to be.”

He further said that Serum Institute of India’s Covishield jab will be used in the initial phase of the vaccination drive.

“They [Serum] already have five crore doses available and they will be able to give that in initial phase where we will vaccinate three crore people,” he said. “Gradually, we will build on it and by the time Bharat Biotech data will also be available.”

Guleria’s comment came after Congress leaders raised concerns over granting emergency use approval to Bharat Biotech’s vaccine before the completion of its third phase trials. Earlier on Sunday, Drugs Controller General of India chief VG Somani announced the approval for restricted emergency use of Serum Institute of India’s Covishield and Bharat Biotech’s Covaxin shots.

Covaxin is the country’s first indigenous vaccine developed by Bharat Biotech, a company based in Hyderabad, with backing from the Indian Council of Medical Research and the National Institute of Virology. However, not much is known about the safety and efficacy of this vaccine in clinical trials. Data of third phase trials of the vaccine have reportedly been submitted to the drug controller, but is not in the public domain.

Meanwhile, Guleria asserted that the vaccines being developed in India are safe and praised them, suggesting that they are cost-effective and easy to administer, as they can be stored in temperatures between 2 to 8 degrees Celsius, reported ANI.

“When we look at any vaccine, safety is of paramount importance and therefore it goes through various stages of study,” he said. “All the data are being critically looked at by the regulatory authorities and experts and only then an approval is given. I do not think we should be concerned.”

He said that the Bharat Biotech vaccine has robust data in Phase I and II trials to suggest that it was a safe vaccine.

Speaking on the dosage regimen of the vaccine, Guleria said that two shots will be administered 28 days apart and it would take around two weeks after the second jab for the antibodies to develop in a person, reported ANI. He also said that various vaccines are not interchangeable and the two doses should be of the same type.

For active cases of coronavirus, the AIIMS director suggested them to defer the vaccination by at least 14 days after their symptoms are resolved.