Although the State has been maintaining a Test Positivity Rate (TPR) of less than 3% for the past week, the detection of 407 more cases of the Delta (B.1.617.2) variant from samples collected a month ago has now again put the focus on genome sequencing.
Delta variant cases in the State, which stood at 318 till Wednesday, shot up to 725 on Friday. This strain has been labelled a variant of concern (VoC) by the World Health Organisation because of its ability to evade an immune system response.
Retrospective samples
Members of the State Genomic Surveillance Committee said the high number of Delta cases being detected from retrospective samples clearly indicates that the second wave in the State was largely driven by this variant.
“Although the detection of more Delta cases is not a matter of concern now, it is clear that this variant was responsible for the high influx of cases in the second wave,” said V. Ravi, who heads the Genomic Surveillance Committee.
“These are samples that were collected four weeks ago. As per the guidelines issued by the Indian SARS-CoV-2 Genomic Consortia (INSACOG), we have been sequencing 300 samples sent from the 10 sentinel sites in Karnataka every month. So far, we at NIMHANS have sequenced and reported 994 samples and 600 more are pending,” said Dr. Ravi, who is also the nodal officer for genomic confirmation of SARS-CoV-2 in the State.
Asserting that the sequencing would take a minimum of 15 days, he said, “The good news is that we are not finding any more new variants. Although Delta has been circulating all over the country, it is important that we sustain the level of sequencing and maintain the low TPR now,” he said.
U.S. Vishal Rao, Dean of Centre of Academic Research at HCG Cancer Centre, who is a member of the Genomic Surveillance Committee, said there was a need to keep a much closer eye to monitor emerging new variants by accelerating the process of genome sequencing. “This is to ensure we will be able to mount a much faster public health response, especially in the wake of an impending third wave of COVID-19,” he said.
“We found the Delta variant in December, but our public health response started only in April. Now we should be able to track in a much systematic manner,” he said.
Concurrent sequencing
Giridhara R. Babu, a member of the State’s COVID-19 Technical Advisory Committee (TAC), said concurrent genomic sequencing was the need of the hour. “We should continue with genome sequencing and at the same time watch out for new clusters. The second wave may be subsiding, but even if a cluster of five or more cases is reported from any building, the mortality should be low,” he said.
C.N. Manjunath, nodal officer for labs and testing in the State’s COVID-19 task force, said screening of people coming from Maharashtra and Kerala should be done strictly. “As we will not get a clinical picture of the emerging new variants unless thousands are infected, all public, social and political gatherings should be banned at least till December,” he said.
