Bharat Biotech’s Covaxin has been found to neutralise the UK variant with “similar efficiency” as the strain used for making the vaccine and hence “dispels the uncertainty of possible neutralisation escape” following vaccination.
Bharat Biotech’s Covaxin has been found to neutralise the UK variant with “similar efficiency” as the strain used for making the vaccine and hence “dispels the uncertainty of possible neutralisation escape” following vaccination, says the results posted on bioRxiv preprint server. Preprints are yet to be peer-reviewed and published in medical journals. The work was carried out by researchers from ICMR and Bharat Biotech, Hyderabad.
The sera from people vaccinated with Covaxin were tested against the same strain used for making the vaccine, another strain found in India but different from the one used for making the vaccine and the UK variant.
The median ratio of 50% neutralization of sera was found to be 80% for the UK variant and 90% for the strain circulating in India but different from the one used for making the vaccine, says Dr. Samiran Panda of ICMR and one of the authors of the preprint.
The study was conducted using the sera collected from 38 people who have been vaccinated with Covaxin during the phase-2 trial. Researchers from ICMR’s Pune-based National Institute of Virology (NIV) and Bharat Biotech found that the vaccine has “comparable neutralisation activity” against the UK variant and the strain used for making the vaccine.
The UK variant was isolated and characterised from people returning from the U.K. The variant isolated from UK returnees had “all signature mutations of the UK variant”, they say.
Sera collected from 38 vaccine recipients during the phase-2 trial had “equivalent neutralising antibodies” to the strain used for making the vaccine, the strain circulating in India but different from the one used for making the vaccine and the UK variant.
Explaining how the neutralisation studies are carried out, Dr. Panda said that the virus isolated from people is grown in the lab using cell lines (in this case monkey kidney cell-lines). When viruses successfully grow in them, the pathogenic effects of the viruses are observed in the cells. The sera taken from vaccinated people are then added to the cell line culture system and its ability to prevent the virus from causing pathogenic effects are observed. In this case, the sera taken from the vaccinated people was able to neutralise the virus and hence prevent the pathogenic effects from being produced in the cell lines containing the virus.
The Covaxin developed indigenously can be expected to work against the new UK variant, say Dr. Panda. The preprint says “it is unlikely that the 501Y mutation found in the UK variant would be able to dampen the potential benefits of the vaccine in concern”.
The manuscript has been submitted to the Journal of Travel Medicine for publication, says Dr. Balram Bhargava, Director-General of ICMR