DCGI accepts proposal to study mixing of Covid-19 vaccine doses

The Drugs Controller General of India (DCGI) has accepted a proposal that a research be conducted to analyse mixing a dose each of the two vaccines against the coronavirus disease (Covid-19), Covaxin and Covishield. "Permission has been granted for research study at CMC Vellore on mixing of vaccine doses," news agency ANI quoted Dr VK Paul, Niti Aayog, as saying.

The Subjects Experts Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO) had, on July 29, recommended that a study be conducted in this regard at Christian Medical College (CMC) in Vellore in the southern state. The proposed trial will see 300 volunteers being administered a dose each of Covaxin and Covishield.

Also Read | Expert panel recommends trials on mixing Covid-19 vaccines - Covaxin, Covishield

The study will aim to determine whether two different vaccine doses could be administered for a person to be fully vaccinated against the coronavirus disease, instead of the existing practice of administering twin shots of the same vaccine.

The exercise, however, is different from a recent research conducted by the Indian Council of Medical Research (ICMR) which concluded that combining two different shots is “safe and effective.” The ICMR research had analysed an “accidental” mixing of Covishield and Covaxin in a village in Uttar Pradesh, in May. The incident saw recipients being administered Covaxin as second dose, six weeks after they received Covishield as first. On analysing this, the ICMR found that “combining two different Covid-19 vaccines gives better immune response than two doses of the same vaccine.”

Also Read | Mixing shots safe and effective: Study

Experts, including top virologist Dr Gagandeep Kang, see combining two different vaccines as a way to tackle vaccine shortage, though they also warn that more studies are needed to reach a definitive conclusion to determine the efficacy of this method in preventing Covid-19. Dr Kang, incidentally, is a professor at CMC Vellore.

Also Read | Mixing of vaccines could tackle shortage but more studies needed, says Dr Kang

Covaxin and Covishield are the first two vaccines which were approved by the DCGI for the nationwide inoculation drive, which began on January 16. Covaxin, developed by Hyderabad-based Bharat Biotech International Limited, is India’s first and thus far only indigenous anti-Covid shot. The Oxford University-AstraZeneca shot, on the other hand, is being manufactured locally as Covishield by Pune-based Serum Institute of India (SII). Besides these, three other vaccines, too, have been approved by the DCGI to be used in the country.