Coronavirus in India: The importance of testing for Covid-19

Covid-19 in India: An analysis of death and testing rates across major Indian states indicates that states that test aggressively, will, over time, show lower fatality rates than others.

An analysis of fatality or death rates (proportion of those infected who die) and testing rates (per million of population) throws up some interesting results and serves to highlight an important aspect of the coronavirus disease (Covid-19): states that test more, will, over time (and this is a mater of a few weeks to a month) end up showing lower fatality rates than states that test very selectively.

In the absence of widespread testing, a comparison of death rates is, at best, a road approximation of how the virus has affected various states. (Pratham Gokhale/HT Photo)

To be sure, even the best Indian states (from the perspective of testing) aren’t doing enough, but, in general, states that test more will, over time expand the denominator (people tested), which will reduce the proportion of people found to be infected. It will also serve to reduce the death rate, which is a subset of those infected.

In the absence of widespread testing, a comparison of death rates is, at best, a road approximation of how the virus has affected various states; however, with 7556 people being infected with Covid-19 as of Thursday night, and the death toll crossing 200 (250), it makes sense to look at these numbers. As the numbers change appreciably, HT will revisit this analysis.

On the basis of the current analysis, Madhya Pradesh has the highest fatality rate of 8% and Delhi has done the most testing per million population (594), leaving out Ladakh whose small population skews the number. Maharashtra has tested 274 per million , which puts it in fourth place.

But if, as the state claims, the high number of cases in it (1574 on Thursday night) is a result of aggressive testing, then the state’s fatality rate (currently 7.1%) will reduce over time.