The silent spread of COVID-19 through asymptomatic patients has caught many cities unawares. In an attempt to pre-empt this and to get a clearer idea about the spread of the virus in the city, the Bruhat Bengaluru Mahanagara Palike (BBMP) plans to test people visiting public spaces, such as markets, malls, restaurants, supermarkets and medical establishments.
When compared to other cities in India, the number of positive cases in Bengaluru [currently at 690] is relatively low and the BBMP aims to keep it that way.
The civic body has developed a new strategy called ‘anti-contact tracing’ to uncover new clusters where the virus may be spreading quietly.
Officials plan to combine samples from crowded places with those taken from people’s homes.
The BBMP developed this approach with their data analysis team, which includes experts from the Indian Institute of Science.
Hephsiba Rani Korlapati, special officer, BBMP COVID-19 war room, said that this approach aims to identify clusters quickly. “People are infected days before they develop symptoms. So our approach is to have an adaptive strategy, which also factors in time. Our plan is to not wait but to test quickly,” she said on Sunday.
While contact tracing depends on quickly tracing and isolating all primary and secondary contacts of a positive patient, officials say that ‘anti-contact tracing’ requires more exploratory testing as it involves hunting for new clusters.
B.H. Anil Kumar, BBMP Commissioner, told The Hindu that they will focus on those who have come into contact with a large number of people. “The focus will be on places which have a large footfall,” he said.
Explaining the difference between randomised testing and anti-contact tracing, Mr. Anil Kumar said, “We do randomised testing in containment zones where there is a high probability of people being infected. We do this to see if there is a community spread and ensure that people who are tested positive are shifted. In this case, samples will be drawn from people who visit places with high footfall. This will help us identify new hotspots or clusters”.
The civic body decided to adopt this strategy after they were unable to identify the source of transmission of a few Influenza-Like Illnesses cases. “We will soon evolve the protocol of how and from whom the samples will be drawn,” Mr. Anil Kumar added. Through anti-contact tracing, the BBMP will help collect samples from a cross-section of different households/locations and “combine them intelligently” to discover new clusters. “This will help design better algorithms to pool samples into groups. Some of the other guidelines for this testing is to skip collecting samples from neighbouring houses and sample adaptively,” Ms. Korlapati added.