Bharat Biotech's Covaxin effective on UK strain of Covid-19: ICMR

An Indian Council of Medical Research (ICMR) study on Covaxin shows a comparable neutralization activity of the vaccinated individuals against UK-variant strain.

The ICMR's National Institute of Virology scientist performed the plaque reduction neutralization test using sera collected from the 26 recipients of Bharat Biotech's coronavirus vaccine (COVAXIN) against UK-variant strain.

"A comparable neutralization activity of the vaccinated individuals sera showed against UK-variant and the heterologous strain with similar efficiency dispel the uncertainty of possible neutralization escape," stated document appeared in bioRxiv in a pre-print version.

"We successfully isolated and characterized the SARS-CoV-2 from UK returnees in India with all signature mutations of the UK-variant," noted the NIV- Pune scientist.

"We present the neutralizing antibodies (Nab) titers to underline the efficacy of Covaxin vaccine candidate against SARS-CoV-2 UK-variant and one of the heterologous strains. Sera collected from 38 vaccine recipients, who received Covaxin vaccine-candidate in phase-II trial had equivalent NAb titers to homologous strain and two heterologous strains with the characteristic substitution of the UK-variant," said the authors.

"The median ratio of 50 per cent neutralization of sera was found to be 0.8 and 0.9 when compared with earlier detected SARS CoV-2 strains against mutant UK strain," they said.

"Our study evidently highlighted comparable neutralization activity of vaccinated individuals sera against variant as well as heterologous SARS-CoV-2 strains."

"Importantly, sera from the vaccine recipients could neutralise the UK-variant strains discounting the uncertainty around potential escape. It was reassuring from the neutralizing antibodies data generated in our laboratory that the indigenous Covaxin following its rollout in the vaccination program, could be expected to work against the new UK-variant. It is unlikely that the mutation would be able to dampen the potential benefits of the vaccine in concern," it said.

The ICMR scientist mentioned that they have reported the development of an inactivated whole-virion SARS-CoV-2 vaccine (Covaxin) which elicited remarkable neutralizing antibody response in phase I clinical trial against homologous, and two heterologous strains from the unclassified cluster.

In phase II clinical trial, the vaccine candidate showed noteworthy results with plaque reduction neutralization test. The sero-conversion rate with neutralizing antibodies following vaccination with Covaxin was 99.6 per cent.

It is pertinent to note that the rapid surge in SARS-CoV-2 cases due to the Variant of Concern (VOC) in the United Kingdom (UK) raised concerns in several countries.