Record 90k tests, Covid-19 positivity rate below 2% for the third day in Delhi

The positivity rate has been below 5% for 15 days now, which experts believe is a sign of the spread of Covid-19 being in control.

With 90,354 tests for coronavirus disease (Covid-19) conducted on Wednesday, Delhi scaled up testing further, inching close to its goal of 100,000 tests a day.

A health worker collects a swab sample to test for coronavirus infection, at UGC, ITO in New Delhi on Thursday. (Sanchit Khanna/HT Photo)

Of the tests conducted, 49,102 (54.3%) were done using the RT-PCR method — the gold standard for coronavirus diagnosis. Experts have warned that if the RT-PCR tests slacken, it could catch the Capital off guard if the outbreak begins resurging.

The city recorded 1,363 new cases of the viral infection as per Thursday’s health bulletin. In comparison, Delhi had seen 8,593 new cases in a day on average during the November surge in Covid-19 cases.

Click here for complete Covid-19 coverage

The high number of tests and fewer cases being reported has led to the city’s positivity rate — proportion of samples that test positive — dropping to less than 2% for the third day in a row. This has happened for the first time since the government started reporting the number of tests and cases consistently.

The positivity rate has been below 5% for 15 days now, which experts believe is a sign of the spread of Covid-19 being in control.

Delhi health minister Satyendar Jain had said on Wednesday that according to the World Health Organization the number of tests should be scaled up till a positivity rate of less than 8% is achieved. “A positivity rate of 5% is considered to be optimum, which means sufficient number of tests is being performed. Delhi has had a positivity rate of less than 3% for five days in a row and less than 5% for 15 days in a row. Right now, the positivity rate is about 2% in Delhi. Let us wait and watch how long the 2% positivity rate is maintained,” he said.

Should the government still continue to increase the number of tests? Yes, say experts.

“We should continue testing as many people as we can and we should continue to increase the number of tests as much as we can. When the positivity rate is about 2% to 3% even with a high number of tests, there is confidence that transmission is not taking place very fast. With fewer tests, the positivity rate can be low either because the transmission is low or the tests are not able to capture the positive cases. As the number of tests is increased, the possibility that we are missing cases is reduced,” said Dr Lalit Kant, former head of the department of epidemiology and infectious diseases at the Indian Council of Medical Research.

Delhi also reported 35 deaths due to Covid-19 on Thursday, taking the city’s toll to 10,182. With fewer cases, the cumulative case fatality ratio — proportion of deaths among those who test positive — is 1.66%. In comparison, the national CFR stands at 1.45%.