COVID-19: What explains the low case fatality rate in India

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The case fatality rate in India, which has been falling steadily, has for the first time dipped below the 2.5% mark on July 19; it was 3.2% in the second week of May. There are many factors that could alter the case fatality rate. Increased testing in recent weeks could be just one of them.

The case fatality rate (CFR) in India, which has been steadily falling, for the first time dipped below the 2.5% mark to reach 2.49% on July 19. It was 3.2% in the second week of May. One of the reasons for the dip in case fatality rate could be ascribed to the increased number of fresh cases detected daily. On July 19, over 40,000 fresh cases were reported, the highest for a single day and surpassing the earlier highest record of 35,468 on July 16.

As on July 20, the world average case fatality rate is around 4.2%, and the UK has the highest at about 15.4%, closely followed by Italy at 14.4%. Total number of COVID-19 deaths as on July 20 stood at over 27,500.

Different from Caucasians

Explaining what could be the main reasons for the low case fatality rate in India, virologist Dr Shahid Jameel who is the CEO of the Wellcome Trust/DBT India Alliance in an email tells me: “Assuming the data is correct (and I have little reason to doubt it), there could be biological reasons for it. Young population (75% below 45 years), exposure to other infections making innate immunity stronger and genetic background [could be some of the reasons]. This is also the case for all countries in South Asia, Southeast Asia and parts of Africa, as well. The difference to a Caucasian population is rather stark.”

While it is true that the median age is 26.8 years in India and so a vast majority of India population is relatively young, in 2011, 8.6% (104 million) were above 60 years of age, thus increasing the chances of altering the case fatality rate during the course of the pandemic. Also, it is well known that a large number of Indians in their 30s and 40s have at least one risk factor such as hypertension, diabetes, cardiovascular diseases, which could increase the chances of death from COVID-19. “This is an enigma. But I believe those co-morbidities become important when one develops severe disease and pneumonia. If most people in India are able to restrict the infection early, co-morbidities will have a much smaller role,” Dr. Jameel says.

Death under-reporting

With cities like Delhi and Gujarat were found to be under-reporting COVID-19 deaths, lack of good tracking and recording of COVID-19 deaths particularly when deaths do not occur in hospitals could alter the low case fatality rate seen in India. While concurring that deaths outside hospitals are hard to track and account for, Dr. Jameel dismisses the possibility of under-reporting of deaths playing a significant role in reducing the case fatality rate. He says: “Death is also hard to miss. I believe there may be some undercounting but not a whole lot. The low CFR is not due to this. It will become harder in small towns and villages. The virus must already be there. It’s just that we don’t know too much on account of poor testing and poorer tracing. This is something to watch.”

Another factor suggested as an explanation for the low case fatality rate in India is the possibility that despite the number of cases detected crossing one million, India may still be in the late early stage of the pandemic as new cases are mainly reported only from large cities and towns. “I don’t think so [that India is in late early stage of the pandemic]. We know very little about how much the infection has moved into small towns and villages due to low or no testing in those areas. There is increasing evidence of moving to next tier cities like Thane, Raigad, Pune in Maharashtra. The same biological principles would apply to small towns and villages as to large cities. The population genetics and exposure to infectious disease is similar – the latter possibly more in smaller places,” he says.

Hospital capacity

One more important factor that could sharply alter case fatality rate is the state of preparedness and enhanced capacity to handle cases when they suddenly surge. This was seen in Mumbai, Bengaluru and Delhi, where well-equipped hospitals were stretched beyond their capacities to handle the surge. While Delhi has in the last few weeks increased the bed capacity thus easing the pressure on hospitals, Mumbai and Bengaluru still seem to be struggling. “Mumbai is still struggling and Bengaluru suddenly exploded after doing well early on. We are not out of the woods yet. Must reduce active cases; over 4% growth is too much,” Dr. Jameel says.

The health seeking behaviour of people could also play a pivotal role in altering the case fatality rate. The delay in getting tested even when overt symptoms are present and delay in hospitalisation have led to many people dying within hours of hospital admission. It has been generally seen that people in some States, particularly in the southern States, seek medical intervention quite early during any disease. Besides the good quality of care, the early health seeking behaviour has been particularly good in Kerala, which has so far reported only 43 deaths and has a case fatality rate of just 0.34% compared with 4.4% in Gujarat, which is the highest in India.

“Kerala is different from other southern States. It has a good healthcare system down to the PHC level. It learned from the 2018 Nipah outbreak and kept the preparedness high. It also built trust and did aggressive contact tracing. Other southern States did none of this. Tamil Nadu has already been badly affected. Telangana, Andhra Pradesh and Karnataka are beginning to look quite bad,” he explains.

Published in The Hindu on July 20, 2020

One thought

  1. Amazing, Shahid has not included ‘RTpct false negatives in this analysis. Indeed, there is a huge proportion of false negatives as well as false positives with both numbers varying substantially. Oh. may be Shahid does not want to hrt the prospects of RT-PCR manfacturers/suppliers/technicians!

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