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

Covaxin has similar efficacy and generates immune response against both the UK coronavirus strain and the one found in India, according to a paper published by scientists from the Indian Council of Medical Research (ICMR) and Bharat Biotech. 

The scientists performed a “plaque reduction neutralisation test”, which measures the concentration of antibodies of a virus, on 26 recipients of Covaxin against the UK-variant and the heterologous strain. Sera — the fluid part of the blood called serum that also contains antibodies generated against any pathogen — collected from these 26 people was used to see if it worked against the UK strain of the virus. 

The genome of the UK-variant has 17 mutations, eight of those were in the spike protein domain. Therefore, it appeared that the majority of the vaccine candidates, specifically targeting the spike sequence, might not be able to generate an efficient immune response against the new variants, the researchers said.

The study authored by 10 scientists including ICMR Director General Balram Bhargava, ICMR scientist Nivedita Gupta and Raches Ella of Bharat Biotech, said that it was “reassuring” from the data generated in the laboratory that Covaxin could be “expected to work against the new UK variant”. 

It is unlikely that the mutation will be able to dampen the potential benefits of Covaxin, the researchers noted. 

Samiran Panda, head of epidemiology and communicable division, ICMR, said that since the sero-conversion with neutralising antibodies following vaccination with Covaxin was 99.6 per cent, the vaccine can be expected to be equally effective against the UK strain. Sera collected from 38 vaccine recipients of Covaxin in the phase 2 trials had equivalent neutralising antibody titers to the India strain. 

The comparison showed similar efficiency of the vaccine against both the strains. The paper said that the findings “dispel the uncertainty of possible neutralisation escape”. 

So far more than 150 Covid patients in India have been identified to have the UK strain. 

The researchers had successfully isolated and characterised the UK strain of the virus from UK returnees in India with all signature mutations of that variant. The inactivated whole-virion SARS-CoV-2 vaccine BBV152, called Covaxin, has shown neutralising antibody response in phase I clinical trial against the Indian strain and two heterologous strains from the unclassified cluster. 

The financial support for this study was provided by the Department of Health Research, Ministry of Health and Family Welfare, at the ICMR-National Institute of Virology, Pune. The research paper was published in bioRxiv, a free online archive and distribution service for unpublished preprints in the life sciences.