New Delhi: Corbevax, the Covid-19 vaccine manufactured by Hyderabad-based Biological E, became the first vaccine in India Saturday to be approved as a heterologous (one that does not match the primary vaccine) booster shot.
However, the vaccine may still have a few more hurdles to cross before it is available as a booster dose at vaccination centres.
Approved for heterologous use by apex drug regulator Drugs Controller General of India (DCGI), Corbevax can be administered as a booster dose to those aged 18 years and above six months after the administration of the second dose of their primary vaccine — Covaxin or Covishield — for restricted use in emergency situations.
To formally become a part of the vaccination programme for adults, though — it is already being administered to children between the ages of 12 and 14 — the vaccine needs to get the nod from the National Technical Advisory Group on Immunisation (NTAGI), the highest body of experts that evaluates data on vaccines before they are included in the national programme.
A senior health ministry official, who wished to not be named, told ThePrint: “The data is yet to be examined by the NTAGI, but the regulatory clearance is an important step forward.”
However, if the ministry of health so chooses, it can bring in the vaccine as a booster shot without waiting for the NTAGI clearance, as it had done earlier when the vaccine was introduced into the national programme for children.
Moreover, India’s current guidelines for booster shots require the gap between the second and the third shots to be nine months. That may need to change if Corbevax is to be introduced as an option.
Administered through the intramuscular route, Corbevax, manufactured by Biological E (BE) in association with Texas Children’s Hospital and the Baylor College of Medicine, is a protein subunit vaccine that introduces a bit of the spike protein of the SARS-CoV-2 virus into the body to generate an immune response.
BE has supplied the Government of India with 100 million doses of Corbevax.
What the data shows
So far, about 51.7 million doses of Corbevax have been administered to children.
In a statement, BE said: “BE has conducted a multicentre Phase III placebo controlled heterologous booster clinical trial in 416 subjects from 18 to 80 years of age who were previously vaccinated with two doses of either Covishield or Covaxin at least six months prior to the administration of Corbevax as a booster dose.
“The booster dose of Corbevax increased the neutralising antibody titers in the Covishield and Covaxin groups significantly when compared to placebo.”
“In a subset of subjects evaluated for nAb (neutralising antibodies) against the Omicron variant, the Corbevax booster shot resulted in a significant increase in the nAb titers against the Omicron 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,” it added.
Neutralising antibodies or nAbs are specific to a pathogen and effectively neutralise them.
“There were no severe or adverse events of interest for three months of follow-up after the booster dose was administered,” the statement said.
(Edited by Zinnia Ray Chaudhuri)