Bengaluru: Wastewater surveillance finds high Covid positivity in several areas

While the positivity rate was at 61% for the week ending June 23, it increased to 89% for the week ending July 21

Bengaluru’s Precision Health initiative, a wastewater surveillance programme piloted by the COVIDActionCollab (CAC) to detect early signs of the disease’s outbreak, has shown increased positivity across the city.

While the positivity rate was at 61 per cent for the week ending June 23, it increased to 89 per cent for the week ending July 21.

Recent results showed that 27 out of 28 samples collected from canals and sewage treatment plants across the city reported the virus’ presence.

“Based on the results, sites in Bengaluru that are positive indicate the presence of an active virus but undiagnosed cases or cases no longer infectious but are still shedding the virus. There is no clear indication for the sudden increase in cases, though it is suspected that the transmissibility of the sub-variants of Omicron could be behind this,” explained Dr Angela Chaudhuri, who is spearheading the Precision Health Covid Surveillance initiative.

Dr Bhaskar Rajkumar, who works with the Covid war room at the BBMP, said the trend was similar during the third wave.

“Wastewater surveillance acts as an early sign. In the next one week, these positive areas will start reporting cases even in the RT-PCR tests,” he said.

In the wake of the revelations, the BBMP ramped up surveillance in the areas.

“We have increased surveillance and testing in the hotspots identified through wastewater reports,” Bruhat Bengaluru Mahanagara Palike (BBMP) Special Commissioner (Health) Dr Trilok Chandra K V said.

Dr Angela urged those residing close to the hotspots to follow all safety procedures like wearing face masks always, avoid crowded places, and monitor symptoms
regularly.

‘Nothing worrisome’

Another senior BBMP official said the trend is nothing to be alarmed about.

“Though the analysis gives a warning sign, considering that many might not get themselves tested and the wastewater prevalence may catch such incidents, there is nothing worrisome.

The trend is similar to the positive cases we are detecting through RT-PCR tests. Since hospitalisation is still low, the situation is under control,” the senior official said.