Covid-19: What we still don’t know today
It’s the end of one quarter of the coronavirus disease (Covid-19) pandemic in India. Sure, the first cases in India, three people from Kerala who returned from Wuhan, China, the birthplace of the virus, date back to late January, but the number stayed at three for a long time. The next cases were recorded on March 2, making June 1 (Monday) the end of the first three months of the pandemic’s run in India.
Tuesday, the beginning of the second, saw another milestone – India crossed 200,000 Covid-19 cases. The country ended Tuesday with 207,112 cases, of which 101,070 remain active. It is seventh in the list of countries in terms of number of cases. There have been 5,753 deaths so far and 100,289 have recovered. The country is currently testing just a little under 3,000 people per million population, although some states are doing much more. Tamil Nadu is testing 6,650 people per million; and Delhi 10,979.
The number of daily cases in India continues to rise – the trailing five-day average on Tuesday was 8,025 – as does the number of daily deaths (the trailing five-day average was 215). Last week (on May 26), the corresponding five-day trailing averages were 6,775 daily cases and 154 daily deaths.
There’s still a lot we do not know about the trajectory of the pandemic in India, and this is a good time to revisit these.
One, we have no idea why the death rate in India, 2.8% on Monday, is much lower than the global 6%. Is it because the virus affects Indians differently? Is it because the BCG vaccine, almost universally given to children in India (for decades) helps Indians infected by the Sars-cov-2 virus deal with it better? We don’t know. Nor do we know why the proportion of those needing critical care or ventilator support is lower in India than what it was in Italy and the US, two countries ravaged by the disease.
Two, we have no idea what the actual death rate in India is. That’s because we are likely underestimating the number of cases. Positivity rates – the number of people testing positive to those tested – continue to rise across most states, including hot spots such as Tamil Nadu, Maharashtra and Delhi, which together account for around 57-58% of all cases in India, and 61% of active cases. Across the world, positivity rates continue to increase up to a point as the number of tests increase, then plateau, and finally start dipping. India is yet to reach that stage – indicating that we are still not testing enough, but this will only serve to reduce the death rate further. Indeed, while we do not know what the actual death rate is, we do know that it is probably lower than 2.8% (because we are underestimating cases).
Three, are we also underestimating the number of deaths in India? After all, studies by the New York Times and the Financial Times have shown that many countries are, and significantly.
The fragmented data available says we are not – there is no spike in the number of non-covid deaths in March and April – but it makes sense to wait till we can get more comprehensive data. That’s another question to which the best answer would be: we don’t know.
Four, we do not know how many Indians have been infected by the virus – and are therefore immune to it.
There have been no widespread serological (blood) antibody tests that can provide this information.
Five, we have no idea why the virus affects different geographies differently. For instance, Bengaluru is one of India’s most connected cities; it is home to tens of thousands of migrants from other states (and even other countries), yet it has a fraction of the cases that Delhi or Mumbai have.
It is important we find answers to at least some of these — they will help us deal better with the coming peak.