Delta wave may be factor in rapid spread of BA.2.75: Experts

India's big Delta wave could be a factor in the rapid spread of Omicron sub-variant BA.2.75, experts told the media agency on Friday, following a multi-centre study from Beijing in China hinting the same.

The study, though to be taken with a pinch of salt as per experts, said when a small sample of serum from those who had the Delta breakthrough infection was tested against BA.2.75, the latter seemed to be more immune evasive than BA.4/BA.5. "BA.2.75 seems to be more immune evasive than BA.4/BA.5 in Delta-stimulated immune background, which may explain BA.2.75's growth advantage over BA.4/BA.5 in India," the study said.

Scientists tracking SARS-Cov2 variants in India told the media agency, the China study has hypothized why the sub-variant might have had a growth advantage in India, which was the first and one of the biggest Delta hotspots.

Dr Sanjay Pujari, member of a national Covid task force, said, "The Chinese study assessed the nuetralization properties of serum samples and extrapolated growth advantages of the latest Omicron sub-variants epidemiologically. Findings revealed that antibodies, after a Delta breakthrough infection, cross-protected against BA.4/5 as these strains share common mutations. As per the findings, since mutations found in Delta and BA.4/5 are absent in BA.2.75, the latter could be more immune evasive in individuals who have had a Delta breakthrough infection. This can explain BA.2.75's in growth advantage in Delta stimulated immune background, compared to BA.4/5."