In view of newer sub-variants of Omicron emerging in some States, Karnataka’s COVID-19 Technical Advisory Committee (TAC) has recommended surveillance of sewage in Mangaluru airport as planned and approved earlier. Besides, with the results of sewage surveillance in Bengaluru correlating with the clinical scenario in the city, similar surveillance should be taken up in Belagavi and Kalaburagi, the TAC has recommended.
In the wake of some States reporting newer sub-variants of Omicron BQ.1 and BA.2.3.20, apart from XBB, which is a recombinant of BA.2.75 and BJ.1, the TAC met last week to review the situation. Sewage surveillance is known to have provided early warning on impending local surge of COVID-19 during the emergence of BA.4 and BA.5 sub-lineages of Omicron in June-July this year.
It can be recalled that sewage surveillance taken up in May had shown the presence of possible BA.4 and BA.5 sub-lineages of Omicron in some samples in Bengaluru. However, the Indian SARS-CoV-2 Genomics Consortium (INSACOG) has confirmed it only in the last week of June.
Who carries out surveillance of sewage?
The TAC’s report stated: “The Infectious Disease Research Foundation (IDRF) has been officially conducting sewage surveillance for COVID-19 in BBMP area since June 2022, and has been providing results on a weekly basis every Saturday. The 19th report was submitted on October 15. The results have correlated with the clinical scenario, and recently have shown gradual reduction in the positivity rate that is in sync with the clinical scenario in Bengaluru.”
“In view of the emergence of newer sub-variants of Omicron in different parts of India and the world, it is recommended that the organisation should soon initiate sewage surveillance in Mangaluru airport that was planned and approved already. Also, it is recommended to start similar surveillance in cities in north Karnataka, such as Belagavi and Kalaburagi. The sewage surveillance should continue at no cost to the State Government,” the report stated.
Besides, the TAC has also recommended that Whole Genome Sequencing (WGS), particularly looking for the newer variants, should be expedited.
Vigilance on borders
TAC Chairman M.K. Sudarshan said with the emergence of new sub-variants, there is a need to be vigilant in cities outside Bengaluru that have movement of people across borders.
“Sewage surveillance is known to help in early identification of any impending wave of COVID-19 and notifying the emergence of new variants of SARS-CoV 2, if any, to initiate local public health actions. In June, the IDRF was granted permission to take up sewage surveillance in select sites in Bengaluru city, Bengaluru international airport and Mangaluru airport. However, the exercise is yet to begin in Mangaluru. Hence, we have now recommended it should begin there at the earliest, and also initiated in Belagavi and Kalaburgi,” he said.
State Health Commissioner Randeep D. said waste water analysis is an early detection tool to assess the spread of new sub-lineages and variants in a hotspot area of increased positivity.
“It is an early COVID-19 incidence indicator at the community level. Areas with a high case load detected in sewage surveillance will be prioritised for COVID-19 testing. However, the final certification of such detections would be only after confirmation by INSACOG,” the Commissioner told The Hindu.
So far, 11 samples of suspected monkeypox cases have tested negative in Karnataka. These samples were tested in the Virus Research Diagnostic Laboratory (VRDL) at the Department of Microbiology in Victoria Hospital in Bengaluru. This is the designated laboratory for monkeypox testing in Karnataka.