There is no question now that Tamil Nadu conducts the highest number of tests for COVID-19 in the country. The question is whether the State should be testing more.
As the epidemic has progressed in the State, throwing up a high number of cases every day, over the weeks, the number of tests has also been increasing. But what is the sweet spot that the State has to hit?
Health Minister C. Vijayabaskar said that on average, Tamil Nadu does over 12,000 tests a day (over the last 10 days), and on some days, even 14,000 tests. Without doubt, it is the best figure in India. But as a State that has been hard hit by COVID-19, epidemiologists recommend that it must increase the number of tests dramatically, especially as the lockdown is being eased across the country.
A new analysis from the Harvard Global Health Institute (HGHI) and STAT for the United States provided a guide about by how much each State should up their testing numbers, based on their number of cases. Its director Ashish Jha said: “You can’t just take the national number and scale it to States by their population. You have to base it on the size of the outbreak in the State.”
As per the analysis published in STATnews.com, the researchers, recommending a massive ramp up in testing in some States, work back from the number of deaths on a particular day, say 545 on May 15. They then say that it will be reasonable to assume that this will be an indication of the number of cases on May 1. This is because two weeks is said to be the average time between infection and death. “If 1 out of every 100 people diagnosed with COVID-19 dies (for a “case fatality rate” of 1%), then on May 1 there will be 100 times as many new cases as there will be deaths on May 15; call it 54,500 (545 * 100) cases on May 1 for the country as a whole.”
To use the same metrics for Tamil Nadu, where the fatality rate is lesser (0.68 %), the total number of people infected will be higher (80,147).
“We need to ramp up testing in Tamil Nadu. Chennai, which continues to get the majority of cases, must definitely test more — at least 8,000 cases a day, double of what we are doing now, so that we do not go the Mumbai route,” said Prabhdeep Kaur, epidemiologist and deputy director, National Institute of Epidemiology.
There are no two ways about whether Tamil Nadu has to increase the number of tests, P. Kuganatham, expert committee member and former Corporation Health Officer, said. “It has to. But I suggest that we target everyone in hotspots, close contacts of symptomatic people, front line health workers, elderly with co-morbidities. Testing should increase for these people, and let’s not be afraid of the numbers this will throw up,” he added.
A targeted approach
J. Amalorpavanathan, who recently retired from service in the State health sector, also recommended the targeted approach. “It’s quite clear that respiratory droplets are the main source of spread, and the spread has been, by and large, contiguous. This is clear in Chennai, where contiguous areas of some wards have been affected. Take a street that has a large number of index cases, draw a circle covering streets to the north, south, east and west of that street. Test everyone there. You are bound to catch many more cases,” he said.
A top official said the State was also seized of the idea. “The number of tests have gone up, and they will go up further. Our strategy in Chennai to go into one ward and do an intense screening is in that direction,” he said.
