The detection of BA.2, a sub-lineage of Omicron variant, in almost 80 per cent of the Covid-19 cases sent for genome sequencing by laboratories in Kolkata has raised concern among the city dwellers at a time when India is caught in the throes of a rapidly surging coronavirus cases.
The samples were sent for genome sequencing between December 22 to 28 and nearly 80 per cent of them were found BA.2 positive with CT level below 30, indicating high viral load.
In the samples sent by one laboratory, 34 Covid-positive samples were found with BA.2. One sample was Omicron BA.1 and eight were Delta and Delta plus. Of the 17 Covid-positive samples sent by another lab, 14 were Omicron and belonged to the BA.2 lineage and the rest Delta. Findings on the 50 samples sent by the third lab showed that 35 were BA.2.
Speaking to TOI, immunologist Dipyaman Ganguly from the Indian Institute of Chemical Biology said that the findings of the genome sequencing are indicative of BA.2 being the sub-lineage that is dominantly circulating in the community in Kolkata and adjoining areas.
“It is possible that BA.2 is causing the local cluster infection. Even as this sub-lineage is different from its other siblings, genetically it belongs to the same family and hence there is no significant difference in the clinical course of the disease,” TOI quoted Dipyaman Ganguly as saying.
Shelly Sharma Ganguly, AMRI Dhakuria microbiologist said that almost 70% of the samples tested positive to Omicron, mostly of the BA.2 lineage, this was a week ago hence the presence of Omicron is likely to have increased manifold by now.
Earlier in December, the government had decided to send all positive samples with CT value under 30 for genome-sequencing to detect community transmission of Omicron. the decision was however reversed a week later when it was clear that community transmission of Omicron had begun.
At present, the health department has asked labs to send only those samples that have foreign travel history. RN Tagore International Institute of Cardiac Sciences microbiologist Swatilekha Banerjee, confirmed that Omicron is replacing Delta adding that though there is an indication about the BA.2 subtype being more prevalent, they need a bigger sample size to draw a conclusion
The BA.2 strain commonly known as the ‘stealth version’ can be detected only through genome sequencing and constitutes one of the sub-lineage of the Omicron variant which has now been split into three sub-types namely BA.1, BA.2, and BA.3.
As per reports while BA.1 is dominantly circulating in Maharashtra and other states, rapidly replacing the Delta variant, the sub-type BA.3 has not yet been detected in India. BA.2 has been detected in those who had traveled abroad recently whereas almost none infected with BA.1 has any travel history.
The Omicron variant of Covid has in less than a fortnight surpassed the Delta strain in Kolkata’s population with seven out of 10 Covid-19 samples collected in the last week of December and sent for genome sequencing turning out to be this ‘variant of concern’, according to the National Institute of Biomedical Genomics (NIBMG) in Kalyani.
Read all the Latest India News here
Comments
0 comment