The Drugs Controller General of India has approved a study on mixing Covid-19 vaccines Covishield and Covaxin, the Centre said at a press briefing on Tuesday.

“To my knowledge, there was a study on mixing vaccines to be done by CMC [Christian Medical College] Vellore [in Tamil Nadu],” NITI Aayog Member (Health) Dr VK Paul told reporters. “The permission for the research study has been granted.”

In July, the Central Drugs Standard Control Organisation’s Subject Expert Committee had recommended allowing the institute to conduct the study, PTI had reported.

“The expert committee after detailed deliberations recommended granting permission to CMC, Vellore for conducting the Phase-4 clinical trial covering 300 healthy volunteers for mixing of Covid-19 vaccines Covaxin and Covishield,” an unidentified official had told the news agency.

Last week, an Indian Council of Medical Research study had found that mixing two vaccine doses was not only safe but produced a better immune response.

The study involved three groups: 18 people in Uttar Pradesh who were accidentally administered one dose of Covishield and a second dose of Covaxin in May, 40 people who got both doses of Covishield and an equal number of those who were inoculated with both doses of Covaxin.

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Mixing Covishield, Covaxin creates better immune response than two doses of same jab: ICMR study

“Immunogenicity profile against Alpha, Beta and Delta variants [of Covid-19] in heterologous group [those who received two different vaccines] was superior; IgG [Immunoglobulin G] antibody and neutralising antibody response of the participants was also significantly higher compared to that in the homologous groups [those who got two doses of the same vaccine],” the authors of the study had said.

However, they added that since the sample size was small and the participants were studied just 60 to 70 days after receiving their first dose, more studies will be needed to conclusively prove if mixing vaccines could help generate a better immune response.

Currently, the government has not approved the mixing of two different Covid-19 vaccines. The ICMR study has not been peer reviewed either. It was published on medRxiv, an online journal for unpublished reports on medical sciences.

Centre on booster shots

At Tuesday’s press briefing, Paul said that the National Expert Committee on Covid-19 Vaccination was looking into whether people needed to be given booster shots. A booster shot is a third dose of a Covid-19 vaccine aimed at increasing protection against the disease.

“I would say we are watching the science for the need for such imperative very carefully, global work as well as certain studies in the country are being instituted and we are looking at it very deeply,” Paul was quoted as saying by PTI. “As you know, WHO [World Health Organisation] called for a moratorium for booster doses so let us watch this and see how it can be taken forward.”

On August 4, WHO chief Tedros Adhanom Ghebreyesus had called for a pause on developed countries’ plans to administer booster shot of vaccines.

“I understand the concern of all governments to protect their people from the Delta variant,” Tedros had said. “But we cannot accept countries that have already used most of the global supply of vaccines using even more of it, while the world’s most vulnerable people remain unprotected.”

In July, Israeli President Isaac Herzog had received a third shot of the coronavirus vaccine, kicking off a campaign to give booster doses to people aged over 60, according to Reuters.

In the same month, United States also signed a deal with vaccine makers Pfizer-BioNTech to buy 20 crore additional doses of their Covid-19 jabs. These doses will be used to inoculate children and also as possible booster shots, according to Reuters. However, the country’s health regulators are still assessing the need for a third dose.

The United Kingdom’s Department of Health and Social Care also unveiled a plan in June to provide booster shots to some vaccine beneficiaries later this year and in 2022.