Biological E's Corbevax gets a boost, as govt allows mixing vaccines

Health ministry nod to the Biological E vaccine as 3rd dose after Covishield or Covaxin, CoWIN to be updated within a week

The health ministry has approved Biological E’s Covid-19 vaccine Corbevax as the third shot after two doses of Covishield or Covaxin for all adults, clearing the decks for the first heterologous booster in India.

So far, India was using the same vaccine as the third dose or precaution shot (homologous boosting). Countries like the US and Canada have allowed mixing the mRNA vaccines made by Pfizer and Moderna for booster doses.

Government sources on Wednesday confirmed that Corbevax has been approved as the booster shot or third dose after two doses of Covishield (Covid-19 vaccine made by Serum Institute of India) and Covaxin (manufactured by Bharat Biotech). This is the first time India has allowed mixing vaccine types.

According to a source, Corbevax is to be administered as a booster six months after two doses of Covaxin or Covishield for all adults. Necessary changes to the Co-WIN portal are expected to be made within a week’s time.

The approval comes after recommendations made in recent weeks by the National Technical Advisory Group (NTAGI) that had reviewed data submitted by Biological E (BE). The Drugs Controller General of India (DCGI) had okayed Corbevax as a heterologous booster on June 3.

“Recently, BE has furnished its clinical trials data to the DCGI who, after a detailed evaluation and deliberations with Subject Experts Committee, granted approval for administering Corbevax vaccine as a heterologous booster dose to people who have already taken two doses of either Covishield or Covaxin. BE’s clinical trial data showed that the Corbevax booster dose provided significant enhancement in immune response and excellent safety profile required for an effective booster,” the company had said in June after it received the DCGI nod.

BE has conducted a multi-centre Phase III placebo-controlled heterologous booster clinical trial in 416 subjects aged 18 to 80 years, who had been vaccinated with two doses of either Covishield or Covaxin at least six months prior to the administration of Corbevax.

The company has claimed that the Corbevax booster dose increased the neutralising antibody titers in the Covishield and Covaxin groups significantly when compared to the placebo. There were no severe or adverse events of interest for three months of follow-up after the booster dose was administered, it added.

A subset of subjects evaluated for neutralising antibodies (nAb) against Omicron showed that the Corbevax booster shot resulted in a significant increase in the nAb titers against the coronavirus variant.

“After the booster dose of Corbevax, Omicron nAbs were observed in 91 per cent and 75 per cent of subjects who had received primary vaccination by Covishield and Covaxin respectively,” BE had said in June, adding that the Corbevax booster also resulted in enhanced cellular immune response.

The NTAGI was reviewing the data on immune response generated by this vaccine when administered after two doses of Covishield and Covaxin.

Corbevax is approved for children aged 12-14 years as part of India’s Covid-19 vaccination drive. Around 68.5 million doses have been administered to adolescents.

BE had supplied 100 million doses to the Centre till June. The company declined to share further production and supply plans.

Into the mix

• Corbevax approved as 3rd shot 6 months after 2 doses of Covishield or Covaxin
• DCGI approved Corbevax as heterologous booster on June 4
• NTAGI was reviewing data on immune response generated by Corbevax given as 3rd shot
• BE has conducted phase 3 trial on 416 subjects as part of mixing trial of Corbevax as booster
• It claimed that subjects had significant increase in neutralising antibodies after Corbevax booster