A technician prepares test samples in a Covid genome-sequencing laboratory at the Institute of Liver and Biliary Sciences in New Delhi. (Bloomberg)
NEW DELHI: Most Omicron variant infected patients of Covid-19, during the last week of December 2021, had no travel history, which indicates that there was eventual community transmission, according to a study conducted by the Department of Clinical Virology, Institute of Liver and Biliary Sciences, New Delhi.
"The respiratory specimen of all RT-PCR confirmed positive cases between November 25 -December 23, 2021, collected from five districts of Delhi were subjected to whole-genome sequencing. Complete demographic and clinical details were also recorded. Hence, we analysed the formation of local and familial clusters and eventual community transmission," the study noted.
The study also stated, "Out of the 264 cases during this 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%)."
It stated that most of the Omicron cases were asymptomatic (50.61%) and did not require any hospitalizations.
"A total of 72 (87.8%) cases were fully vaccinated. Around 39.1% (32) had a history of travel or contacts while 60.9% (50) showed a community transmission," it added.
The study showed a steep increase in the daily progression of Omicron cases with its preponderance in the community, which was observed from 1.8% to 54%.
As per the interpretation of the study, this is among the first from India to provide the evidence of community transmission of Omicron infection with significantly increased breakthrough infections, decreased hospitalization rates, and a lower rate of symptomatic infections among individuals with high seropositivity against SARS-CoV-2 infections.