Covid-19: Delhi HC right on need to test asymptomatic 

Indeed, as data from Karnataka and Kerala—two states that had reported success in controlling spread early in the pandemic—show, wider testing helps catch more infections.

The Delhi High Court asking the Delhi government to revisit its testing strategy for Covid-19 cases in the national capital in order to accommodate asymptomatic cases should serve as a cue for all states to do this. Indeed, the rising number of Covid-19 cases in the national capital, after economic activity has returned to near-normal, makes this an imperative. Given the wide gap between the serosurvey’s indication of Covid-19 infection in the capital—a little over 29% of the population—and the case infection rate (CIR) of 12.5%, as gleaned from daily testing data at the time that the survey was done, it is clear that there are many who are getting infected and simply not getting reported. And it is quite likely that a large number of these ‘missed’ Covid-19 cases could be those who were truly asymptomatic. With ICMR clarifying that it is an advisory body and that states are free to tweak testing strategy as per their capacities, the ball is not just in the Delhi government’s court but also in that of other states. Indeed, as data from Karnataka and Kerala—two states that had reported success in controlling spread early in the pandemic—show, wider testing helps catch more infections. Karnataka was conducting just 4,345 tests per million population on June 1, and had detected 3,221 cases by then with a case-infection rate of 1.1%; the corresponding figures for Kerala were 2,171, 1,269 and 1.6%. By September 1—after the phased unlocking—while the tests per million had risen 10 and 22 times in Karnataka and Kerala, respectively, the total cases detected had risen 106 and 59 times, with the corresponding CIR reaching 11.8% and 4.5%!

The Delhi HC has paved the way for testing on-demand in the national capital, by instructing the Arvind-Kejriwal-led government to examine whether a doctor’s prescription should be kept mandatory or optional, or done away with entirely, for RT-PCR testing. The CIR in the national capital stood at 11.03% on Tuesday and, as FE has pointed out before, this has perhaps more to do with the fact that testing in the national capital since mid-July has been driven largely by rapid antigen testing (RAT) that fails to detect as many cases of infection as the RT-PCR test does. Though RT-PCR testing has been increasing over the last few days—which perhaps explains why there has been a spurt in reported cases lately—it is still a low number; indeed, on Tuesday, RT-PCR (including CBNAAT/TrueNAT) tests numbered 7,198 while RAT numbered 17,000. Given the combined RT-PCR testing capacity of private and public laboratories in the national capital territory is around 14,000, the actual testing through this mode in Delhi is just about half, a fact that the High Court made special note of. Unless states start using their RT-PCR capacity to the maximum possible extent to detect the maximum number of cases and allow on-demand testing—with efforts in parallel to step up testing capacity—stalling the spread of the disease will be difficult. Indeed, while Bihar’s testing per million has risen 42 times between June and September, RAT accounts for nearly 90% of the state’s tests; as a result, even though the state’s total number of cases shot up from 3,815 to 1,36, 457 over the period, it is able to show a falling CIR, at 4.3% today versus 5% on June 1 and 9.3% on August 1. Contrast this with Tamil Nadu, which is exclusively doing RT-PCR/CBNAAT/TrueNAT testing—the state hasn’t shown wide fluctuations between July (ICMR released guidelines for RAT on June 14) and September. If states don’t want their healthcare capacities strained, they will need to test the asymptomatic to limit their role in the spread of Covid-19.