Delta major variant responsible for breakthrough infections during second wave of COVID-19 in India

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 was observed in only three cases (0.4 per cent)."

This clearly suggests that vaccination reduces the severity of disease, hospitalization and mortality, said the study. Therefore, enhancing the vaccination drive and immunizing the populations quickly would be the most important strategy to prevent further deadly waves of the COVID-19 and would reduce the burden on the health care system, it added.

The study is a preprint and it was approved by the Institutional Human Ethics Committee of ICMR-NIV, Pune.

It was conducted with intramural funding for 'Molecular epidemiological analysis of SARS-CoV-2 circulating in different regions of India' of Indian Council of Medical Research (ICMR), New Delhi provided to ICMR-National Institute of Virology, Pune.

( With inputs from ANI )