As Delhi testing hits high, 1,404 Covid-19 infections added
Delhi reported 1,404 new cases of Covid-19 on Saturday, the highest single-day increase since July 18, according to data from the Delhi government’s daily health bulletin. Till Friday, the Capital had recorded a weekly average of 1,018 cases.
However, the increase in the number of detected cases is likely due to an increase in testing. In fact, Friday’s testing numbers were the highest in the Capital since the Covid-19 crisis began, with over 24,500 samples collected.
The positivity rate — the percentage of people who test positive among those tested, at 5.7%, was lower than the week’s average of 6.6%.
The number of tests being conducted during the week had been low – dipping to 9,295 in the bulletin released on August 4, and the positivity rate for the day had touched 7.25%.
The number of tests for the viral infection being conducted in Delhi had shot up in the third week of June after rapid antigen testing was rolled out.
More than three in four of the 24,592 tests reported in Saturday’s bulletin were conducted using these rapid test kits. A person testing positive on the kit, is considered to be a “true positive” or truly having the infection. However, due to low sensitivity, the test tends to throw false negatives. Hence, the government tests the symptomatic people who have tested negative with the rapid kit using RT-PCR again.
The “slight increase” in the number of cases should not be a cause of concern, say experts.
Dr Puneet Mishra, professor in the department of community medicine at All India Institute of Medical Sciences said, “A jump from 1,200 cases to 1,400 cases just for a day is not a cause for worry. It could be because of the increased testing. If we compare the number of cases now to what was being reported daily in Delhi just two months back, the difference is huge. For now, we need to observe the trend. Ups and downs are okay, unless the numbers keep increasing consistently over the next week or two.”
A high prevalence of antibodies in the population could also be the reason for transmission slowing down in Delhi.
“The number of cases in Delhi have gone down even as the cases continue to rise in the other parts of the country. It is likely that the prevalence of antibodies will be higher in the second round of sero-surveillance. If it is 40 or 50%, it might be the reason transmission is slowing down in Delhi. There are just two ways of gaining immunity to the infection – either through a vaccine or through natural infection. There is no vaccine against Covid-19 at present, so immunity can be developed only through natural infection. It is a good thing if a high percentage of people develop the immunity without getting sick and needing hospitalisation. At least for the time being, they will be protected against the infection and also protect others through her immunity,” said Dr Mishra.