Door-to-door Covid screening in a containment zone in Belapur Navi Mumbai on July 7, 2020. (Express Photo: Amit Chakravarty)

India Coronavirus Numbers: As the number of diagnostic tests for novel Coronavirus is increasing in the country, so is the positivity rate. This means more number of people, from among those who are being tested, are found to be infected with the disease. The positivity rate had crossed 6 per cent mark for the first time on June 20, and has risen swiftly thereafter. At present, the positivity rate is around 7.09 per cent.

Positivity rate is a good indicator to assess the prevalence of the disease in the community. The rise in positivity rate means that the growth in the number of confirmed cases is outpacing the growth in the tests being conducted. And this is happening mainly because the criteria for testing is still restrictive in most states.

The number of new cases in India since June 15.

As scientists have been pointing out, the more the number of tests that are carried out, greater would be the chances of finding infected cases. However, people are not being randomly tested. Because of limited testing capacities, states are being selective in testing people. For example, many states are testing only people who are showing signs of symptoms, or those who are higher risk of attaining the disease, like the primary or secondary contacts of an already infected person. Now, there is a much greater likelihood of these people testing positive, compared to other people. So if the total number of tests are rising, but still only symptomatic cases, or those at high risk, are being tested, the positivity rate would progressively rise.

In fact, states that have restrictive criteria for tests have a much higher positivity rate. An example is Maharashtra where the positivity rate is almost 19 per cent. Mumbai has an even higher positivity rate, of around 24 per cent.

As the testing criteria becomes more relaxed, the positivity rate is likely to decline. Mumbai, for example, has declared that from now on, testing would be open for everyone, not just symptomatic cases, or those who have been prescribed a test by a physician.

The number of tests being carried out in the country has seen a significant rise in the last two months. More than two lakh samples are being tested every day, and the cumulative number of tests crossed the one crore mark two days ago.

📢 Express Explained is now on Telegram. Click here to join our channel (@ieexplained) and stay updated with the latest

But the growth in the number of cases has been more rapid. On Tuesday, about 22,750 new cases were detected across the country, only slightly higher than the previous day. More than 7.42 lakh people have so far been detected with the virus so far, of which more than 4.56 lakh have already recovered from the disease.

Top ten states with maximum caseload

For the third day today, the numbers reported by Maharashtra and Tamil Nadu, the two largest contributors of new cases, showed a marginal decline, but Delhi had a rise. There was a small decline in the new cases being reported from Karnataka as well, but Telangana once again reported more than 1,800 cases on Tuesday.

For the last three days, there has once again been a decline in the growth rate of confirmed cases. The current seven-day compounded daily growth rate of cases happened to be 3.46 per cent, the lowest ever.

One state that is showing signs of a surge in the last few days is Odisha. The state has been reporting more than 500 cases for the last three days, and has added more than 3,300 new cases in the last one week. It is now growing at a rate of 5.47 per cent, much higher than the national rate.

📣 The Indian Express is now on Telegram. Click here to join our channel (@indianexpress) and stay updated with the latest headlines

For all the latest Explained News, download Indian Express App.

© The Indian Express (P) Ltd