Bharat Biotech's ¡®Covaxin¡¯ neutralises the Brazilian variant of SARS-CoV-2, the novel coronavirus behind the Covid-19 pandemic, scientists at Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV) said in a new study.
The findings come a couple of weeks after the ICMR announced that indigenously-developed Covid-19 vaccine is effective against the UK variant (B.1.1.7) as well as the Indian (double mutant) variant B.1.617--the latter is yet to be designated a ¡°variant of concern¡± status.
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A variant of interest (VOI) can become a variant of concern (VOC)--a higher threat--if it has demonstrated increased transmissibility, increased virulence, a change in clinical disease, or decreased effectiveness of efforts to control or treat the Covid-19 disease.
The new study, published in bioRxiv--an open access preprint repository for the biological sciences--found an increased immunity in individuals against the Brazilian variant after receiving two doses of Covaxin.
¡°This study shows that the two-dose Covaxin regimen significantly boosted the IgG (immunoglobulin G, a type of antibody) titer and neutralizing efficacy against both the variants compared to that seen with natural infection,¡± the researchers said.
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¡°Results confirm 1.92 and 1.09 fold reductions in the neutralizing titer against B.1.1.28.2 variant in comparison with prototype D614G variant with sera of vaccine recipients and natural infection respectively,¡± the study added.
Previously, the government said that both Covishield and Covaxin are effective against the UK and Brazilian strain. The research work regarding the South African variant is still ongoing.
Meanwhile, Russia's Sputnik V vaccine--the third vaccine to be used by India in its immunisation drive against Covid-19--has proved to be less effective against the South African Covid-19 variant but neutralises the UK variant effectively.
The genomic sequencing of over 13,000 samples showed that 11 per cent of them were infected with the UK strain (most prevalent in Punjab), while the B.1.617 (double mutant) variant was found in 7 per cent of the samples (mostly from Maharashtra), National Centre for Disease Control director Sujeet Kumar Singh said late last month.
The good thing is that the South African variant, which sees significantly reduced vaccine efficacy, has been found in less than 1 per cent of the total samples.
Scientists noted a rise from 28 per cent of samples having UK variant in the second week of March to 50 per cent in the last week of March. India recorded a total 948 cases with UK, South Africa and Brazil variants--variants of concern--till the first week of April.