Surge in Covid-19 cases beats growth in testing in race against time

India has been adding record number of coronavirus cases to its tally almost every day, each time beating the previous high. On Thursday, it witnessed 24,879 new cases, adding yet another high to its record. With rise in cases, states too have ramped up testing. But is it enough to stem the tide of the Covid-19 rampage?

Mass testing, early tracing and isolating Covid cases are crucial in containing the virus. India Today Data Intelligence (DIU) calculated weekly growth rates of cases and compared them with the growth rates of testing in different states and found that after a month of lifting lockdown, the speed of testing is slower than the speed at which cases are spreading in almost all of them.

Across India, in the first week of July, the growth rate of Covid-19 testing was 2.45 per cent, while cases recorded a growth rate of 3.48 per cent. India conducted 14 lakh tests in this period, of which 1,37,776 people tested positive. At this rate, cases would double every 20 days in India, while testing will take 28 days to double.

Till July 8, India recorded a total of 7.42 lakh cases after testing around 10.47 million people, which is the fifth highest number for any country. However, with respect to its population, the number seems small as hardly 7,800 tests are conducted per million population, which ranks 138th according to “Worldometers”.

Better performers

Like the spread of the virus, testing too shows regional heterogeneity, with some states doing exceptionally better than others. Delhi and Madhya Pradesh are the only bigger states where the average weekly growth rate of testing is higher than cases.

In the first week of July, Delhi’s growth rate of testing was 3.5 per cent, while the growth rate of cases was 2.3 per cent. Data shows Covid-19 cases are doubling every 31 days in the Capital, while tests are doubling every 20 days.

As of July 8, Delhi conducted more than 7 lakh tests and recorded a little over one lakh cases. As a result, its positivity rate has come down to less than 10 per cent; it was above 10 per cent since May 22. According to India COVID19 Apex Research Team (iCART), the reproduction rate (https://covidtoday.in/) of the virus (Rt) has also come down to 0.91.

Rt is the number of people that one infected person can pass on the virus to. Ideally, it should be less than one.

In Madhya Pradesh cases recorded a growth rate of 2 per cent in the first week of July, while tests grew at 2.3 per cent. This shows that cases are doubling every 34 days and testing every 30 days. As of July 8, MP conducted 4.37 lakh tests, and recorded 15, 627 cases.

But unlike Delhi, Rt and positivity rates in MP have moved up slightly. The state had an Rt of 1.21 and a positivity rate of 3.6 per cent.

The growth rate of testing in Uttar Pradesh remained higher than cases till July 6. However, things changed the next day as the state witnessed a sudden rise of 1,332 cases, its highest daily addition this month. As of July 8, UP conducted 9.2 lakh tests and reported close to 30,000 cases.

Alarming situation in some states

Karnataka has become the latest hotbed of Covid-19. The state recorded a jump from 16,500 to 27,000 cases within a week – a growth rate of 8.4 per cent. At the same time, testing grew by only 2.5 per cent. Till July 8, Karnataka recorded a total of 28,877 cases after testing more than 7 lakh people, of which one lakh were tested since the turn of the month.

Assam too is facing a rapid growth in cases. The number of infections jumped from 8,500 to 12,500 in the first week of July, while testing increased from 4.2 lakh to 4.8 lakh only. At 13,336 cases, the doubling time is 11 days with a growth rate of 6.5 per cent. Tests are doubling every 28 days with a growth rate of 2.4 per cent.

In Tamil Nadu, Covid-19 cases grew at 3.9 per cent, doubling every 17 days, while testing grew at 2.7 per cent, doubling every 25 days. This despite conducting 14 lakh tests, twice than Delhi, and having thrice the Capital’s population. Till July 8, Tamil Nadu reported around 1.18 lakh cases.

In Maharashtra, Gujarat, Uttar Pradesh and Haryana, the difference between growth rates of coronavirus cases and testing is negligible, but the former leads the race.

Expert speak

Just before lockdown was lifted, DIU had reported on an AIIMS-led study (https://www.indiatoday.in/diu/story/ease-lockdown-after-peak-or-increase-tests-says-aiims-study-on-covid-19-1683992-2020-05-31) that said India needed to scale testing if it wishes to reopen before hitting a peak.

According to Professor Giridara Gopal, an epidemiologist at AIIMS, Delhi, and one of the founders of iCART, “When the number of tests is increased, it’s essential to consider the break-up of how many of them were done in symptomatic and asymptomatic cases. States could show a reduction in positivity rate by testing symptomatic cases alone.”

“Asymptomatic individuals could go undetected and spread the virus so much that in weeks, new clusters could arise. It is also necessary to note that individuals are getting recovered/discharged on a daily basis, and hence, if their tests are also factored in the positivity rate denominator, there is a possibility of false reduction. Therefore, a uniform definition for all indicators is mandatory,” Prof Gopal added.

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