Bharat Biotech’s Covaxin has been found to neutralise the U.K. variant with “similar efficiency” as the strain used for making the vaccine and hence “dispels the uncertainty of possible neutralisation escape” following vaccination, say results posted on the 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 U.K. variant.
The median ratio of 50% neutralisation of sera was found to be 80% for the U.K. variant and 90% for the strain circulating in India, but different from the one used for making the vaccine, Dr. Samiran Panda of ICMR and one of the authors of the preprint told The Hindu.
The study was conducted using 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 and Bharat Biotech found that the vaccine has “comparable neutralisation activity” against the U.K. variant and the strain used for making the vaccine.
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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 (monkey kidney cell-lines in this case). 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 is observed. In this case, the sera taken from vaccinated people was able to neutralise the virus and hence prevent pathogenic effects being produced in the cell lines containing the virus.
The U.K. variant was isolated and characterised from people returning from the U.K. The variant isolated from U.K. returnees had “all signature mutations of the UK variant”, the authors 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 U.K. variant.
The indigenously developed vaccine Covaxin can be expected to work against the new U.K. variant, says 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, Dr. Balram Bhargava, Director-General of ICMR told The Hindu.
Published - January 27, 2021 05:01 pm IST
