India coronavirus numbers explained: Why spike in deaths, along with jump in cases, is worrying.

India : coronavirus cases numbers explained: The increase in the number of deaths have coincided with a big jump in the number of new infections being detected. But there may be not a correlation between the two.

India coronavirus cases and deaths: For three consecutive days now, the number of Coronavirus-related deaths in the country have exceeded 1,000. There have been days earlier when more deaths have been reported, but those have mainly been a result of some state clubbing together large number of previously unreported deaths. Never before have more than 1,000 deaths been reported on two consecutive days. And in the last three days, there has been no unusual addition of deaths from previous days.

The increase in the number of deaths have coincided with a big jump in the number of new infections being detected. More than 75,000 new cases have been discovered in the last two days. Before this, the numbers had remained well below 70,000 for more than three weeks. So, it can be tempting to correlate the rise in cases and increase in deaths as part of the same trend. But that is not the case.

The people who die are not from the same lot who are found infected on that day. They are usually from groups that are been detected positive two to three weeks earlier. There have been reports of people dying within a day or two of being detected positive, but these are small numbers. In most cases, deaths happen after several days of the person getting infected. But there is no fixed time lag, and therefore, it is difficult to correlate any particular episode of spurt in death count to any corresponding rise in the number of cases.

It is because of this reason that the case fatality numbers, a metric used regularly to assess how fatal the disease is, have also to be read with caution. India currently has a case fatality ratio (CFR) of 1.82 per cent, almost half that of the world average. This means that 1.82 per cent of people detected positive in India have died, whereas, globally this number is close to 3.4 per cent. The CFR in India has been on consistent decline, and that too is a positive sign.

But the 1.82 per cent number is slightly erroneous because it is obtained by dividing the total number of detected cases at present, with the total number of deaths that have happened. But as we have seen, people do not die the same day they are infected. The deaths happening today are from the pool of people who were infected with the disease two to three weeks earlier. So, a more accurate CFR would be obtained by using the total number of infected people from two to three weeks ago as the denominator. This would be substantially less than the number of infected people today, and therefore, a more accurate CFR would be much higher than the current 1.82 per cent.

If we use the total number of infected people from two weeks ago, the CFR goes up to about 2.4 per cent. But even this would not be entirely accurate, because, as pointed out earlier, there is no fixed time lag for the deaths. Getting an accurate CFR, when the epidemic is still evolving, required careful tracking of individual cases, and some research groups in the country are working on this.

But the real assessment of how fatal the disease has been can be known only when the full spread of the disease is known. Since most infected people are never detected, the actual number of infected people is believed to be much larger than the detected numbers show. This has been revealed by the several serological surveys conducted in the country. These surveys have suggested that the actual spread of the virus could be 20 to 40 times the numbers that are detected through diagnostic tests. In such an eventuality, the real fatality rate would be much less. Scientists believe that by the time the current epidemic comes to an end, the real fatality rate would not be more than one per cent.

On Thursday, more than 77,000 new cases were detected in the country, about 2,000 more than the previous day. India is not just reporting the highest number of cases in the world as of now, but it has recorded the highest number for any country anytime during this pandemic. The death count has crossed 61,500, and it is most likely to overtake the death count in Mexico by Friday. That would leave India only behind the United States and Brazil in the number of people who have succumbed to Covid-19 disease. In the United States, more than 184,000 people have so far died due to the disease, while Brazil has so far counted more than 118,000 deaths.