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, Hindustan Times’ sister publication Live Hindustan has reported, citing India Today. 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 Tamil Nadu’s Vellore.

The proposed trial will see 300 volunteers being administered a dose each of Covaxin and 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 proposed study, 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.”

Experts, including Dr Gagandeep Kang, the country’s top virologist, 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.