Indian vaccines should be used as boosters without any delay, say experts

Indian vaccines should be used as booster shots without delay to combat the Omicron variant, public health experts said, instead of waiting for mRNA-based ones that are currently not available in the country.

This comes even as the government's advisory group on Covid-19 is awaiting data from the National Institute of Virology (NIV), Pune before it considers recommending booster doses.

Experts said mRNA vaccines work best as boosters against Covid-19, but in the absence of these, people who have received Serum Institute of India (SII)'s Covishield should get Bharat Biotech's Covaxin as a booster shot, while protein sub-unit vaccines like Corbevax - developed by Biological E - and Covovax - produced in India by SII under license from US-based Novavax - will work better for those who have received Covaxin.

mRNA, or Messenger RNA, vaccines - such as those developed by French vaccine maker Moderna - teach cells to make a protein, or a part of it, to trigger an immune response.


Immunity Concerns Trigger Booster Demand
"mRNA vaccines work best as boosters but that's not available in India. Protein vaccines like Covovax work well," said Shahid Jameel, a virologist and director of the Trivedi School of Biosciences at Ashoka University.

According to a recent study published in medical journal Lancet, the protection offered by the Oxford-Astra Zeneca Covid-19 vaccine (made in India by SII) declines three months after a person receives two doses.

The demand for booster doses has intensified after doctors and public health experts expressed concern over waning immunity and the growing evidence that boosters can help mitigate the debilitating effects of newer strains such as Omicron, first identified in South Africa last month which is rapidly spreading across the globe.

"...out of the available vaccines in India, those people who have received Covishield should get Covaxin, which will give viral antigens. However, for those who have received Covaxin, protein sub-unit vaccines like Covovax and Corbevax can be used as boosters," said K Srinath Reddy, president, Public Health Foundation of India.