At 10 Percent, Why Is West Bengal’s COVID Mortality Rate So High?
A combination of low testing, inadequate medical infrastructure and demographic factors explain the spike.
The state of West Bengal, at about 10 percent, has the highest COVID-19 mortality rate or Case Fatality Ratio (CFR) among all the states of India. The case fatality ratio, according to the World Health Organisation (WHO), is the number of deaths divided by the number of confirmed cases of a particular disease.
As of 6 May, the West Bengal government had announced 1,456 confirmed COVID-19 cases. The death toll of the state stood at 144, of which the government classified 72 as “COVID-19 deaths” and 72 others as “deaths due to co-morbidities where COVID-19 was incidental”.
The state’s high mortality rate has also been flagged by the Ministry of Home Affairs recently, in a letter to the state government.
To put this in context, Maharashtra, which has the highest number of COVID positive cases so far, has a mortality rate of 3.97 percent. Slightly more than the national average of 3.42 percent.
What Leads To High Mortality Rates?
According to John Hopkins University, the mortality rate or CFR can vary from place to place depending on the following factors:
- Rate of testing: If testing rates are low, CFR tends to be higher. If more people are tested, then more people with milder or asymptomatic cases are tested positive. This brings down the CFR.
- Healthcare infrastructure: CFR increases if the healthcare system is under more pressure. For example, if hospitals are overwhelmed and are unable to treat as many patients as is the requirement, CFR will rise.
- Demographic composition: CFR tends to be higher in regions where the average population is more aged.
In the case of West Bengal, a combination of all three factors come into play.
Low Rates Of Testing In West Bengal
As of 6 May, the West Bengal state government was doing 334 sample tests per million. The state reported its first COVID case on 18 March.
Before 21 April, when the Home Ministry's Inter Ministerial team sent a letter to the state government complaining about low testing, the state was testing 68 samples per million.
At the same juncture, Maharashtra was testing 742 per million, while Gujarat, another state with a large number of positive cases, was testing 614 per million. This number had increased to 1,519 and 1,235 per million, respectively, on May 3, when West Bengal was testing only 252 per million, reports IndiaSpend.
The number of positive cases in the state have also been increasing exponentially since the MHA’s letter, at an average of 62 per day.
In an interview to India Today on 11 April, the Director of the National Institute of Cholera and Enteric Diseases (NICED), which is ICMR’s nodal body in Kolkata, said that they hadn’t even received 20 samples the week before.
“There is a big drop. Last week we didn’t even have 20 samples per day. Number of samples being sent is determined by the state government, so if they send more samples, we are able to test more. I think sample collection has not been as per the recommendation. So number tests being done in Bengal is also less”, NICED Director, Santa Dutta, said in the interview.
In an interview to The Quint of 22 April, spokesperson of the Trinamool Congress, that runs the Bengal government, Derek O’Brien blamed the stunted testing in the state on faulty testing kits sent by the ICMR.
The NICED, on 19 April, said that the testing kits being sent to West Bengal by the ICMR were faulty as they had not been pre-standardised.
Epidemiologists in Kolkata, that The Quint spoke to, suggest, however, that with the testing numbers in the state increasing, the CFR will come down. They also note that initially West Bengal was testing only critical cases which then resulted in a higher death toll.
Adequacy Of Healthcare Infrastructure
As of 6 May, West Bengal had 16 ICMR certified testing centres, according to the state government.
Initially, the NICED was the only approved testing centre. The number was gradually increased to eight and then sixteen, after permission was granted by the Centre. The number of COVID hospitals in the state stands at 67.
Again, compare this to Maharashtra had at least 80 dedicated COVID hospitals in the state, three weeks ago, on 19 April.
However, the government has faced flack as reports emerged of district hospitals being too crowded or too far for patients to be adequately checked. A case in point is the North Bengal Medical College in Siliguri, which acts as a COVID centre for all of North Bengal as well as Sikkim.
Concerns about safety of front-line healthcare workers also emerged in the state with doctors complaining that they had been supplied torn raincoats instead of PPE kits.
Some private facilities, like the 400 bed Peerless Hospital in Kolkata, had to shut down after multiple doctors and healthcare staff tested positive for the virus.
However, on paper, the state claims that it has 8070 earmarked COVID 19 beds, which have an occupancy percentage of just 13 percent. The number of government ventilators in the state stands at 392.
This number shows that the state is not at a point where it is overwhelmed by the case burden of COVID cases.
Epidemiologists also say that that the high CFR could also be attributed to the initial under-preparedness of the state infrastructure to deal with critical cases. As the state infrastructure became more equipped, the mortality rate started to show a decline.
According to a report by The Indian Express, research by scientists of the Chennai-based Institute of Mathematical Sciences (IMSc) show that though West Bengal, Bihar, and Jharkhand had a combined case load of less than 1,200 on 29 April, these three states had the highest rate of growth in the country, as measured by their reproduction numbers. Reproduction number is the number of persons who are infected, on average, by an already infected person.
IE also reported that West Bengal has one of the lowest doubling rates in the country. Doubling time is the amount of time it takes for cases to double. The report also quotes researchers from IMSc saying that Bengal seems to be following Maharashtra’s trajectory but is delayed by three weeks.
This, along with the state’s exponential rise in positive cases, as mentioned earlier, give rise to the apprehension that the state might soon be overwhelmed, further increasing the mortality rate.
Testing Of Older Demographic
Experts also point towards the state’s initial trend of testing and treating patients of an older demographic who were showing symptoms.
This was an advisory by the ICMR too.
This meant that the state was reporting more critical cases, which again added to the death pool.
However, experts also point out that the state’s CFR has decreased from 15 percent earlier to 10 percent now. If testing continues to increase at the present rate, it is expected to go down to 5 percent in the next few weeks.
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