New Delhi: A study conducted by the Indian Council of Medical Research (ICMR) on variants responsible for the second wave of COVID-19 has revealed that the major strain responsible for the breakthrough is the Delta variant. As per the WHO classification, the Delta variant has been designated as a variant of concern due to increased transmission and higher immune evasion, whereas the other two sublineages of B.1.617 namely B.1.617.1 and B.1.617.3 with E484Q are grouped in VUI[25].
"B.1.617 variant and its lineage B.1.617.2 were primarily responsible for the surge in COVID-19 cases in Maharashtra state. Delta (B.1.617.2) and Kappa (B.1.617.1) was detected among 60 per cent of the clinical specimens of the COVID-19 cases collected from Maharashtra during January and February 2021." according to the study. "The rapid rise in the daily infection was observed in India with the dominance of Delta variant which accounted for >99 per cent of all sequenced genomes in April 2021," it further stated.
Talking about the infections after vaccination, the study said, "The present study revealed the infection among breakthrough cases predominantly occurred through Delta variant indicating its high community transmission during this period followed by Alpha and Kappa variants. In our study, 67 cases (9.8 per cent) required hospitalisation and fatality were observed in only three cases (0.4 per cent)."