May 16, 2021 12:57:56 am
MUMBAI’S DAILY Covid-19 Test Positivity Rate is showing a steady decline from 27.94 per cent on April 4 – when the city recorded its highest single-day cases at 11,206 – to 6.57 per cent on May 14, when the number dropped to 1,657.
Test Positivity Rate (TPR) is the percentage of people who have test positive for the virus from among all those who have undergone tests. It helps health officials find the current level of virus transmission in the community and also get an understanding on whether enough tests are being conducted when compared to the number of people getting infected.
TPR is high when most people who are getting tested are infected and is low when most samples test negative.
The city’s TPR, has remained below 10 per cent since May 6, should also be viewed in co-relation with the number of daily tests being conducted. Trends show that when test numbers declined, the TPR went up.
However, with Mumbai currently conducting around 30,000 tests a day, the reduced TPR is indicating that the infection is coming under control.
“TPR is fundamentally estimated because we want to eliminate the testing frequency. We have to consider all factors, yardsticks and not just TPR. TPR is not the indicator of the number of tests being conducted, it is a complex indicator. Trends show that the less number of tests are conducted, the more will be the TPR,” said Dr Shashank Joshi, a state Covid-19 task force member.
Questions, however, are being raised about the decrease in the number of daily tests being conducted in the city. The number has declined from 51,319 on April 3 to 43,525 on April 29. Typically, the number of daily tests have fallen over the weekend. On all four Sundays in April, the figure remained below 40,000, with the lowest at 28,328 on April 25.
The number of daily tests being conducted between May 6 and May 14 has been in the range of 25,000 to 35,000.
“We also need to recognise that along with TPR, we are looking at the doubling rate, recovery rate, drop in active cases and case fatality rate. I still feel that we need to increase the number of tests, but overall, the trend is clear that infection rate is coming down,” said Joshi.
Civic officials said that before the state government announced stricter curbs on the movement of people on April 21, they were testing people at crowded areas such as daily markets, malls and railway stations.
“Currently, we are conducting targeted testing – people with symptoms and contacts of the infected. If there are over five cases in a single building, we are setting up testing camps. However, such instances have drastically reduced. The number of people coming to private labs as well as in walk-in and free facilities set up at health posts to get tested have also reduced,” said Kiran Dighavkar, Assistant Municipal Commissioner, G-North ward.
Joshi added: “There are many reasons why the test frequency has gone down – primarily being the change in ICMR guidelines that has stopped repeat tests for individuals, leading to straight 30 per cent decline in the numbers. Number of asymptomatic individuals seeking to undergo tests have reduced. Also, no elective surgery and very less non-Covid hospitalisation taking place currently, which require a negative test report.”
The Indian Council of Medical Research on May 4 had updated its testing guidelines, stating that “RT-PCR tests must not be repeated in any individual who has tested positive once either by RAT (rapid antigen test) or RT-PCR” to reduce the burden on laboratories.
“The need for RT-PCR tests in healthy individuals undertaking inter-state domestic travel may be completely removed,” it had added.