Delta variants lineages reduces Covaxin antibodies, ICMR study

Antibodies produced in response to Covaxin were reduced when tested against the Delta variant and its sublineages but continued to be high enough to remain protective, according to a study by scientists at the ICMR-National Institute of Virology. The antibodies were collected from fully vaccinated individuals, some of whom had reported breakthrough infections, and yet others who had recovered from COVID-19 and tested in the laboratory against lab-cultured coronavirus variants belonging to the Delta, AY.1 and AY.3 lineages. Their average antibody levels were nearly thrice that of the COVID-naive individuals but reduced by nearly 50% when tested against the Delta variant, by 65% against AY.1 and 72% against AY.3. The comparative analysis of all the groups revealed that the B.1.617.3 variant seems to be less susceptible to neutralisation followed by Delta AY.1 and Delta variants compared to B.1,” the authors who include several senior scientists from the ICMR, note in their preprint publication, which is yet to be peer-reviewed. “However, with the observed high titers, the sera of individuals belonging to all the aforementioned groups they would still neutralize the Delta, Delta AY.1 and B.1.617.3 variants effectively,” they note.