Covaxin is effective against the Delta Plus (AY.1) variant of SARS-CoV2 virus, a new study by the Indian Council of Medical Research (ICMR) has said. Despite a slight reduction in neutralisation antibody titres, Covaxin is effective against Delta, AY.1 (Delta Plus) and B.1.617.3 variants, the study added.
Covaxin has been developed by Bharat Biotech and ICMR.
“Our research showed that Covaxin could still neutralise Delta, AY.1 and B.1.617.3 variants,” Dr Samiran Panda, head of epidemiology and communicable diseases, ICMR, told The Indian Express.
Delta variant has also been identified as the leading cause of breakthrough infections globally among vaccinated individuals. Recently, the Delta variant has mutated to Delta AY.1, AY.2 and AY.3. Of these, Delta AY.1 variant (Delta Plus) was first detected in India in April 2021 and subsequently, from 20 other countries as well.
Till now, the prevalence of Delta AY.1 is found to be low in India and 70 cases of coronavirus Delta Plus variant were found in genome sequencing by INSACOG. However, there has been no information on the efficacy of currently available vaccines against the Delta AY.1 variant.
Sera of vaccines among Covid naïve, recovered cases with full vaccination and breakthrough cases demonstrated 1.3, 2.5 and 1.9-fold reduction against Delta variant in comparison to B.1 variant respectively, the new ICMR-National Institute of Virology study — ‘Comparable neutralization of SARS-CoV-2 Delta AY.1 and Delta in individuals sera vaccinated with BBV152’ — published as a pre-print on bioRxiv, said.
Lead author Dr Pragya Yadav said a minor reduction was observed in the neutralising antibody titer in Covid- 19 recovered cases, fully vaccinated and post immunised infected cases as compared to Covid-19 naive vaccinated individuals.
“However, with the observed high titers, the sera of individuals belonging to all the groups in the study would still neutralise the Delta, Delta AY.1 and B.1.617.3 variants effectively,” Dr Yadav said.
The study had evaluated the IgG antibody titer and neutralising potential of sera of Covid-19 naive individual’s full doses of Covaxin vaccine, Covid-19 recovered cases with full dose vaccines and breakthrough cases post-immunisation Covaxin vaccines against Delta, Delta AY.1 and B.1.617.3.
Despite the sera of Covid-recovered cases with vaccinations and breakthrough cases of infection showing considerable reduction in the neutralisation antibody titre, Covaxin vaccine could still neutralise Delta, AY.1 and B.1.617.3 variants.
“The bottomline is that Covaxin is effective and slight reduction in neutralisation antibody titres is not going to be detrimental for the vaccination programme,” Dr Panda said.
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