#Corona in India: Has it entered Stage 3?

India’s number of cases has already crossed 1000 and is growing at an exponential rate. This is very worrying. There are fears that India has entered stage 3 i.e. community spread. Community spread is the most dangerous stage because it is here that the virus really explodes. Containment becomes near impossible.

Stage 1 means only foreign returned are infected, stage 2 means people who came in their contact are infected. Because the number of these people is generally small (relative to population) and they are easier to trace, so the virus can still be controlled at this stage. But once it moves beyond that, i.e. the general populace starts getting infected in stage 3, there is no stopping.

Although India has very small number of cases compared to other major countries, it was discredited saying India was not testing enough. It made sense – no testing, means no positive. Until 28 March, India’s testing was just about 20 per million – among the lowest in the world. Coupled with figures released 3 days ago that between January 23 to March 23, 15 lakh people entered India, (10 lakhs is 1 million) a real risk of  missing out on testing a lot of foreign returned people exists. So these fears were not totally unfounded.

So, in this article, to assess it, we do a cross country comparison of reported cases and tests done. Corona has started spreading in different countries from different dates. And also in the initial few cases, the spread is very variable and unpredictable. So for every country, we start from the day when the cumulative reported number of cases crossed 50. This happened in India on 10th March, Iran on 24th Feb, Italy on 22nd Feb, USA on 22nd Feb, Spain on 29th Feb, France on 28th Feb, UK on 3rd March and South Korea on 19th Feb. Then (because we have data until 28 March and focus of this study is on India) we look at how the number of reported cases has grown in 19 days since the day 1 i.e. when the total number crossed 50. The result can be seen in the left panel in the figure below. India is clearly the best i.e. shows least number of cases on day 19 at 987. All the countries are far worse except USA which is close at 1301 cases on day 19.

Does this mean that the virus’ spread has been least in India? Well, before answering in yes, we must consider two more facts. A) Our closest US went on to become the most infected country in the world with around 1.5 lakh (0.15 million) cases today i.e. 37th day since it crossed 50. B) Our testing rates are one of the lowest in the world, both in absolute numbers (only about 27,000 tests so far) and tests per million (approx 20). If we don’t test, we don’t report positive, simple.

To address this issue of under-testing, we take a snapshot of number of positive cases various countries reported when they did their 30,000th test. Why 30,000? Because a) this is where India stands today and remember this is an India centric study, and b) We can’t compare the ratio of positive cases reported to total tests done when total tests are very high. Because by the time countries began testing those huge numbers, virus had already entered stage III and a larger proportion of their population had become infected. In other words, as we test more and more, days also pass, and virus spreads more in population and proportion of positive cases in total tests done also increases.  So for an apples to apples comparison, we must compare when countries were around their 30,000th test. Around and not exact, because we don’t have daily data of tests conducted for any country except USA.

The right panel in the chart above clearly shows even here India fares much better here too. It has the lowest number of positive cases per hundred tests done (3.66%) around the 30,000th test level. And although by the end of 19th day, USA was closest to us in terms of total number of positives, they had done only around 7700 tests compared to our 27000. This means by day 19, they were already 3.5 times more virulent than us. Coming back to positive to total tests ratio around 30,000th test mark, USA’s figure was 13%, Spain was already at 49%(!) and France at 15%. This means at this stage, these countries had already entered community spread stage. Only UK was close to us at 5% however, their’s figure is for 64,000th test and because proportion of positives increases with more tests, around 30,000th test they too would have been closest to us. Now one way to hack this percentage is to test only low risk cases (to give less number of positives) but India’s testing policy has been to test highest risk patients first. I doubt any other country would be capturing any higher risk patients only.

So, this means if we want to estimate how our corona trajectory will look like, our best estimate would be UK, right? Well yes, but for one thing. UK initially had refused to take the utmost important decision of locking down. As a result, it let virus spread and only locked down on the 34th day i.e. on 23 March. But by then, the virus had already spread far and wide and it had 8961 cases or 175 cases per million population. Contrast this with India, where we imposed a total lockdown on 13th day itself i.e. 22nd March when our total cases reported were just 396 or 0.22 per million population.

I know there have been massive migrant labor movements after that and leakages in lockdown and home quarantines etc., and will estimate their impact in a later post, but we have clearly (at least it seems so at present stage) averted the disaster which the western countries find themselves in presently. And given our much inferior health infrastructure capacity than most of these countries, I think by acting early and decisively we have saved lots and lots of lives.

However, the battle is far from over. If anything, this highlights the paramount importance of lockdown. I know its painful, very very painful, but it is our only good enough chance at survival right now. Its going to be a long journey. Take care and stay indoors!