Even as India has massively scaled up testing for covid-19, the proportion of people found positive among those tested is on a steady decline. However, the country continues to add close to 80,000 new cases every day, closing in on Brazil which has the world’s second highest count of covid-19 cases.
Data from the Indian Council of Medical Research (ICMR) showed India on Tuesday crossed 3.7 million covid-19 cases with deaths of over 66,000, even as the average positivity rate fell. “The spikes in percentages appear every Sunday when there is a drop in the tested numbers usually by about 22%. Else, there has been a significant drop in the positive percentage from 15 August onwards,” said Girdhar J. Gyani, director general, Association of Healthcare Providers (India) (AHPI).
“The average positive percentage has dropped from 9.4% till 15 August to 7.9% by the 31st. The overall positive percentage stands at 8.46%,” he added.
In fact, if the average month-on-month positivity rate is considered, the increase in confirmed cases has fallen 180% between 20 June and 30 July, and by a further 51% between 30 July and 30 August. Public health experts said that lower positive cases with increased testing could be due to the new range of tests. With states and Union territories rapidly increasing capacity, India’s cumulative tests crossed 43 million on Tuesday, with over 12 million tests in the last two weeks alone. The highest daily tests were conducted by Tamil Nadu, Maharashtra and Uttar Pradesh, which together accounted for nearly 34% of countrywide testing.
With 1,016,920 tests in the last 24 hours alone, India’s daily testing capacity has crossed 1 million. Weekly average tests are up four-fold since the first week of July, the government said.
“India is boosting testing as part of addressing covid-19, but the type of testing needs to be viewed. The gold test is the RT-PCR test, but along with that, we had switched over to a cheaper and quicker method called Rapid antigen test, which gives the result in 15-20 minutes. But the test is also less reliable with low accuracy and was only meant to be used in viral hotspots,” said Suneela Garg, director, department of community medicine, Maulana Azad Medical College, University of Delhi.
After Delhi started antigen tests in June, other states followed suit.
“During 29 June to 28 July, a total of 587,590 tests were done, of which 63% were antigen tests, but less than 1% of those who tested negative went on to have a PCR test which could be responsible for the overall fall in positive cases,” added Garg. Similarly, Karnataka started antigen testing in July, targeting 35,000 tests a day across 30 districts. In the beginning of August, as compared to antigen testing, there was much less PCR testing.
“About 38% of those who initially tested negative but took PCR test due to symptoms came out to be positive. A few other states like Telangana and Odisha also scaled up rapid antigen testing,” Garg said.
The Mumbai municipal corporation has reported that 65% of those who tested negative in antigen test were found positive in the PCR test, said Garg, adding that this test will allow faster detection, but will only detect highly infectious individuals with high viral load.
“In the bargain, we potentially miss out many individuals. We may meet the demand for more testing, but we cannot have the true extent of the outbreak unless it is backed up by PCR testing in all negatives tested by rapid antigen testing.” Garg said rapid antigen tests should be done only in hotspots and containment zones under medical supervision.
In the last 24 hours, five states witnessed the highest new case count, with Maharashtra (11,852), Andhra Pradesh (10,004), Karnataka (6,495), Tamil Nadu (5,956) and Uttar Pradesh (4,782) accounting for 56% of confirmed cases added in the last 24 hours.