3,882 new cases in Delhi, highest since sept 19; positivity rate jumps to 6.61%
So far, 344,318 people in Delhi have been infected and 6,163 fatalities recorded in the seven months since the first case was reported in the city on March 2.Updated: Oct 23, 2020, 01:31 IST
The number of daily cases of the coronavirus disease (Covid-19) recorded in Delhi continued on an upward trend, inching closer to the 4,000-mark as the Capital added 3,882 infections on Thursday — the highest since September 19.
So far, 344,318 people in Delhi have been infected and 6,163 fatalities recorded in the seven months since the first case was reported in the city on March 2.
The positivity rate — the proportion of tests that come out positive for Covid-19 — was at 6.61% on Thursday, the Delhi government’s daily health bulletin showed. The seven-day average of positivity rose from 5.4% to 6.4% in the last two weeks.
Experts say the recent increase in the number of samples testing positive for Covid-19 could be attributed to the rise in molecular tests such as the RT-PCR that are more accurate in diagnosis than the antigen tests.
Over 16,000 RT-PCR tests daily have been conducted for the last two days. On average 14,877 daily RT-PCR tests were carried out in the last seven days, accounting for 27.9% of the total tests conducted in the time period. This is an increase from the average of 11,528 tests per day carried out the week before (making up 23.2% of the total tests) and the 9,254 two weeks ago (19.2% of total tests).
The molecular RT-PCR test amplifies the genetic material of the virus collected using a throat or nasal swab and is very sensitive. The alternate Rapid Antigen Tests (RAT) are cheap, can be deployed in dispensaries and clinics, and give results within 15 minutes. But they are not as sensitive as RT-PCR and are prone to throwing up false negatives i.e. diagnosing people who are infected with Covid-19 as uninfected.
“The sensitivity of the rapid antigen test is about 60 to 65% at best; if we use more RT-PCR tests, of course we will detect more cases. But I think the current increase in the cases is not just because of the RT PCR tests; there might be some increase happening for real. It is the festive season, people are stepping out, going shopping and all this leads to increase in the transmission of the infection and higher number of cases,” said Dr Shobha Broor, former head of the department of microbiology at the All India Institute of Medical Sciences (AIIMS).
The Delhi government had scaled up testing three-fold to about 60,000 tests a day in September after the city saw a surge in the number of cases of Covid-19.