Delta continues to be the dominant COVID-19 strain in India

As a third wave of COVID-19 pandemic grips India, a study has highlighted that the delta strain continues to be dominate. The study was conducted by the Department of Clinical Virology, Institute of Liver and Biliary Sciences, New Delhi. It collected respiratory specimen from five districts of Delhi between November 25 – December 23, 2021.

“Out of the 264 cases during the study period, 68.9% (182) were identified as delta variant and its sub-lineages, while 31.06% (82) were omicron variant with BA.1 as the predominant sub-lineage (73.1%),” the report said. “Most of the omicron cases were asymptomatic (50.61%) and did not require hospitalizations. A total of 72 (87.8%) cases were fully vaccinated. Around 39.1% (32) had history of travel or contacts while 60.9% (50) showed a community transmission.” The study highlighted  a steep increase in the daily progression of omicron cases with its preponderance in the community, which was observed from 1.8% to 54%.

Dr Pradeep Vyas, additional chief secretary of health department, in a letter to his colleagues on Wednesday said that the delta variant was found in 68% samples, out of over 4,200 analyzed, while the remaining 32% patients were found infected with the omicron strain.

It should be noted that the omicron strain which was initially detected in South Africa in November 2021 started spreading in India from the first week of December. Till Friday night, Maharashtra has reported 1,605 omicron cases, while its overall COVID-19 infection tally has jumped to 71,24,78.

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Dr Vyas said that since November 11, 2021, the samples of 4,265 COVID-19 patients were sent for genome sequencing. “The results of 4,201 cases have been issued, which indicate that omicron variant was detected in 1,367 cases or in 32%, while the prevalence of delta variant was found in the remaining 68% cases,” he said. “Of the 2,40,133 active COVID cases in Maharashtra, till Wednesday, 90% patients were in home isolation or in COVID care centers. We have seen three weeks of the present surge in COVID infections. Till January 12, there were 2,40,133 active COVID-19 cases, of which 90.9% were either in home isolation or in COVID care center. Only 21,783 patients or 9.1% of the total active cases were in hospital.”

74.2% had mild symptoms and 2.3% needed ICU or oxygen support. Only 700 patients, which is about 0.29% of the total active cases, were on ventilators.