Covid-19: R-naught dips in Chennai; experts ask for strict adherence to masks – Times of India

Chennai News
CHENNAI: While fresh cases in Chennai continue to increase, the effective reproduction number or R-naught, one of the key epidemiological factors, is now dropping in Chennai, indicating a slow growth rate.
R0, or basic reproduction number indicates how many new cases one infected person generates. If the R0 is two, then we would expect each new case of a disease to produce two other infections.

The number of fresh cases the Greater Chennai Corporation has been reporting over the last one week has been increasing every day, yet the rate of increase has slowed down.
On Tuesday, for instance, Chennai added 6,484 new cases – which is 294 cases more than what the city reported on Monday. Last week, the city was reporting an increase of anywhere between 500-1200 more cases compared to its previous day tally. With this, the R-naught, which climbed to nearly 3.7 on New year’s eve is now 2.9. As a reflection, although the daily cases increased the rate of increase is slowing down.
“So, the drop in R-naught is good news,” said National Institute of Epidemiology director Dr Prabhdeep Kaur. “Testing has remained standard. But the drop must continue. If the effective R is reduced below one, cases will come down. With Pongal holidays, this week will be crucial for the city,” she said.
Experts have asked for stringent adherence to masks and social distancing. The average test positivity rate – the number of people tested positive among every 100 people tested in the week – is hovering above 10 in Chennai compared to around 4.5 in Tamil Nadu.
Public health officials say despite several curbs, there will be an increase in inter-district movement for a week from Wednesday. When people leave the city to their hometown there is risk of infections in the districts. This means even districts that have test positivity rate below one such as Dindugul, Tiruvarur, Pudukottai and Nagapattinam have an increased risk of transmission. Similarly, when they return after celebrations, there is risk of cases increasing within the city.
Although hospital occupancy is low, the rising numbers can overwhelm the healthcare system and tire healthcare workers. Experts including WHO chief scientist Dr Soumya Swaminathan, have asked the state to consider introducing rapid antigen tests during the recent expert committee meeting with the state government.
She earlier told the TOI that the state has a policy to use only RTPCR tests. “But antigen tests are now being used across the world and many kits are highly sensitive. It will be useful to make spot antigen testing mandatory for all members taking part in large public meetings or indoor events,” she said.