25% of all Bengaluru's Covid containment zones are in apartments

Of the 136 containment zones in Bengaluru, about 25% are set in apartments where the density of population enables the spread of coronavirus.

Municipal officials stated that nearly half of all new primary cluster cases being found in apartment complexes continue to have a travel history. Their presence in apartment complexes sometimes enables faster spread due to the higher population density and in some cases, more restrictive ventilation, experts said.

In addition, the airborne spread of the novel coronavirus among specific apartment units at a large complex in the West Zone has raised fears that other high-rise apartments will report similar patterns of outbreak.

According to the Bruhat Bengaluru Mahanagara Palike (BBMP), 13 out of 35 high-caseload containment zones were in apartments as of Saturday. The remainder were in housing layouts, military installations and a small number of individual homes.

Also read: Covid-19 outbreak at Bengaluru apartment block, airborne spread feared

In Bommanahalli Zone, these four out of five identified high-caseload containment zones are apartments. In Yelahanka, two out of four containment areas are apartments, as are two out of five each in Mahadevapura and South zones. Dasarahalli Zone did not report any apartment clusters.

In RR Nagar and East zones, one out of five high-caseload zones each are apartments while in the West Zone, only one location out of four containment areas comprises an apartment — a tower in the Renaissance Temple Bells apartment, where 21 cases were reported as of Sunday. Apartment residents fear that airborne transmission of the virus had taken place.

Aerosolised transmission

Noted virologist, Dr Shahid Jameel, Director, Trivedi School of Biosciences, said that while further analysis of the Renaissance Temple Bells outbreak was needed, there was nevertheless precedence for the aerosolised spread of viruses from the 2003 Sars-1 outbreak.

“At that time, at an apartment complex in Hong Kong, the virus had apparently spread through pipes carrying faecal matter. But a similar ‘aerosolised’ spread has not been the trend among the outbreaks of the novel coronavirus. The Bengaluru incident is something new,” he said. “One easy fix is that people must open the windows in their bathroom to circulate the air,” he added.

Vikram Rai, General Council Member, Bangalore Apartment Federation, specified that this matter of spread through faecal matter or through aerosols had been specifically asked to the Karnataka State Pollution Control Board (KSPCB) during the initial days of the second wave, but satisfactory answers had not been obtained.

“The BBMP has not taken an official stance on aerosolised or sanitary pipe transmission. If spreading is happening through ducts or pipes, that is a serious risk that we must contain,” he said.

BBMP Special Commissioner (Health), D Randeep, specified that while authorities were concerned about apartment outbreaks, resident welfare associations (RWAs) had been generally conducive to reporting cases to the civic body. “In the end, non-reporting of cases generally backfires against the apartment complex with the formation of a larger cluster,” he said.