In a study conducted by the Indian Council of Medical Research (ICMR) on the variants responsible for the devastating second wave of COVID-19 in India, it was revealed that the major strain responsible for the breakthrough is the Delta variant. According to the study, B.1.617 variant and its lineage B.1.617.2 were primarily responsible for the surge in COVID-19 cases in the state of Maharashtra. Delta (B.1.617.2) and Kappa (B.1.617.1) variants were detected among 60 per cent of the clinical specimens of the COVID-19 cases collected from Maharashtra during January and February 2021.
According to WHO, the Delta variant will soon become the dominant variant in the world and is a growing concern as it causes increased transmission and higher immune evasion, whereas, as per WHO classification, the other two sublineages of B.1.617 namely B.1.617.1 and B.1.617.3 with E484Q are grouped in VUI.
"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 ICMR study further said, "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." The Delta variant has caused havoc in countries like Argentina, England and Indonesia.
Talking about the breakthrough infections, i.e. infections caused after vaccinations, 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 percent) required hospitalisation and fatality were observed in only three cases (0.4 percent)."
The silver lining is that the vaccines reduce the severity of disease, hospitalization and mortality. The study suggested that 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.
The study is in preprint and 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 ANI Inputs)