Kolkata: More people without any underlying comorbid conditions died of Covid-19 during the peak of the second wave of the pandemic in West Bengal, Karnataka and Tamil Nadu than in the peak of the first wave, our analysis of official data reveals. A majority of these deaths were of persons aged under 60 years.
Death without comorbidity refers to Covid-19 cases where a person with no major pre-existing health condition such as diabetes or high blood pressure passed away after contracting Covid-19. It means Covid-19 was the main cause of death. West Bengal, Tamil Nadu and Karnataka are the only three major states systemically providing data related to comorbidities among Covid-19 deceased.
While the intensity of the second wave countrywide has been ascribed to the Delta variant's increased transmissibility by the central government's policy think-tank Niti Aayog, there is little publicly available evidence to examine this variant's role in increased deaths of Covid-19 patients with no comorbidities in states such as West Bengal, where this variant is dominant, say doctors.
Comorbidity-related data should be placed in relation to the proportion of Covid-19 variants in states to gauge their impact, if any, on deaths of persons with no underlying comorbidities, they say. For instance, to assess if the Delta variant had a role in the higher share of such deaths in West Bengal, statistics related to the proportion of variants in Tamil Nadu and Karnataka are required, but unavailable in published form. Further, other states such as Maharashtra and Delhi where the same Delta variant is dominant do not release comorbidity-related data in their daily Covid-19 bulletins.
Doctors call upon the health ministry to release national-level Covid-19 data on comorbidities, or to ask states to release such data uniformly in their daily bulletins, and data on the geographical spread of variants to enable an understanding of what may have caused a spike in such deaths.
The share of deaths of people without underlying comorbidities among all Covid-19 deaths in Tamil Nadu and West Bengal increased threefold during the second wave, data from April-May 2021, when the second wave peaked, and September-October 2020, when the first wave peaked, reveal.
In Tamil Nadu, 23.9% deaths during the second wave were of people with no comorbidities, up from 7.6% during the first wave. In the week ending May 31, the share rose further to 26.2%.
In West Bengal, just over half of all Covid-19 deaths during the peak of the second wave in April and May 2021 had no comorbid conditions involved. Overall, by April 1, 2021, the share of deaths of patients with no comorbid conditions in the state stood at 16%. By May 31, that share had gone up to 28.3%.
Karnataka recorded an 11-percentage point increase in the share of Covid-19 deceased with no underlying comorbidities in the second wave, at 38.2% compared to 27.1% in the first wave. In the week ending May 31, the share in deaths of such patients was even higher at 40.2%.
Share of younger persons, vaccinated later, rises
In all three states, the majority of the deceased without comorbidities were younger than 60 years. In Karnataka, 62% of those who died without any comorbidities were aged below 60. In Tamil Nadu, the share was as high as 80%. West Bengal did not share age-wise break-up of its comorbidity-related data. However, several doctors told us that Bengal's higher share of Covid-19 deaths without comorbidity during the second wave was partly due to a high number of deceased from the under-60 age group.
Among those who died of Covid-19 without any underlying comorbid conditions in the three states, the share of people aged below 60 years has risen during the second wave.
In Tamil Nadu, 71% of the Covid-19 deceased without comorbidities during September-October 2020 were below 60 years. In April-May, this went up to 80%.
Karnataka's data reveal a similar trend. During the peak of the first wave, 48.6% of those who died without comorbidity were aged under 60 years. In the second wave, this went up to 62%.
West Bengal did not share age-wise data in the context of comorbidity, but the state's high share of death without comorbidity was due to the higher number of younger people getting infected by the virus, Arjun Dasgupta, president of West Bengal Doctors' Forum, told IndiaSpend.
"In the second wave, it's the younger people who suffered the most," Dasgupta said. "This has definitely to do with vaccination. The elderly people had received either one or both doses of the vaccine and remained more protected. That is why we, on behalf of our forum, have been consistently saying that the government should prioritise vaccination and carry it out on a war footing to prevent a catastrophic experience when the third wave hits."
The spike in death without comorbidity in West Bengal seemed to be because the pandemic hit the younger people more in the second wave, agreed Sayan Chakraborty, an infectious diseases specialist at AMRI Hospitals in Kolkata. "Younger people generally have less comorbidities than senior citizens," he told IndiaSpend, adding, "The elderly people were mostly getting vaccinated, while the younger population were mobile and more exposed to the virus."
Countrywide, there was a three percentage-point increase in Covid-19 cases among persons aged 21 to 50 years in the second wave compared to the first wave, and an equivalent decrease in cases among persons aged over 50 years, per health ministry data.
Vaccinations for persons aged 60 years and above, and those aged 45 to 59 years with specified comorbidities began on March 1, 2021; for all aged 45 years and above on April 1; and for all aged 18 to 45 years on May 1. By May 31, persons aged 18 to 45 years in Karnataka and West Bengal accounted for 19.7% and 22.2% of all persons vaccinated, respectively. In Tamil Nadu, the proportion for this age group was 33%.
By June 22, the share of 18- to 45-year-olds in total vaccinations stood at 35.8% in Karnataka, 29% in West Bengal and 45.3% in Tamil Nadu, per Covid19 India.
No publicly available evidence on Delta variant's role
The central government has ascribed the intensity of the second wave to higher transmissibility of the Delta (B.1.617.2) variant of SARS-CoV-2, the virus that causes Covid-19. "During the second wave, Delta variant - B.1.617.2 exhibited its effect; its higher transmissibility played a major role in making the wave intense," said V.K. Paul, member (health), Niti Aayog, on June 16.
West Bengal and Tamil Nadu have not formally released any information regarding the proportion of variants in their states. In May, however, the Delta variant was found to be dominant in West Bengal, according to an article published in the science journal, Nature. Nearly 90% of new Covid-19 cases over the first two weeks of June in West Bengal had been affected by the Delta variant, a state health department official reportedly said in mid-June. Tamil Nadu's data regarding the prevalence of strains were unclear, according to this report from early June.
As of June 23, Karnataka had conducted 565 tests to identify Covid-19 variants, of which 318, or 56% were of the Delta variant.
The Delta variant, which first emerged in Maharashtra, later overtook other strains to become the leading variant in many states, including West Bengal Delhi, per the Nature article. The World Health Organization labeled Delta a "variant of concern" at the beginning of June. The Delta variant is "well on its way to becoming the dominant variant globally because of its increased transmissibility", WHO chief scientist Soumya Swaminathan said on June 18.
One distinct feature of the second wave in West Bengal was that the virus was affecting entire families, said Chakraborty. Maharashtra-based public health expert S.P. Kalantri, director and professor of medicine at the Mahatma Gandhi Institute of Medical Sciences and the medical superintendent of Kasturba hospital in Sevagram, concurred: "In the first wave, we were getting more cases of one individual in a family getting infected. But this time, the virus is infecting whole families more often."
"Secondary attack rates [probability of infection occurring among susceptible people within a specific group like a household or close contacts] and household transmission studies support increased transmissibility of the Delta variant," said a Public Health England (PHE) risk assessment report on the Delta variant on June 18.
One possible reason behind the spike in death without comorbidity is that the virus is affecting the lungs much earlier than during the first wave, said Arindam Biswas, an internal medicine specialist at the Rabindranath Tagore International Institute of Cardiac Sciences in Kolkata. "The viral load is quite high and the lungs are getting affected quite early. The cytokine storm has been the mainstay in the second wave," Biswas told IndiaSpend.
The risk of hospitalisation was approximately doubled in patients with the Delta variant compared to the Alpha variant, according to a study of Covid-19 patients between April 1 and June 6, 2021 by Scottish government Covid-19 advisory team members, published in The Lancet medical journal on June 14.
But whether the Delta variant has any impact on the increase in deaths of Covid-19 patients without comorbidities is a question that will have no answer for the time being due to lack of correlated information available in the public domain, experts said.
"The Delta strain, which is now the dominant strain in Bengal, is also the dominant strain in many other states, including Maharashtra. Comorbidity-related data from all those states are required to be placed in relation to the proportion of strains in those states to get any idea about the impact of particular strains, if any," said Saumitra Das, a microbiologist and director of National Institute of Biomedical Genomics (NIBG), Kalyani.
Since states such as Maharashtra and Delhi did not release comorbidity-related data in their daily health bulletins, there was no scope for comparing them with West Bengal.
There could also be a role of genes in enthnic groups behind different levels of impact in different states, added Das, but there was not enough information or research publicly available to come to any understanding about this.
Data related to increasing share of patients without comorbidities in Covid-19 deaths need to be seen in relation to the proportion of different variants of the virus in specific states, said Chennai-based virologist T. Jacob John. "Bengal's high share of non-comorbid deaths, and the difference with that of Tamil Nadu, is intriguing. But due to the lack of uniformity in data provided by different states and the general lack of information in the public domain, it is not possible to explain what may have caused this spike. To assess if variants have any role, we need to know the proportion of the strains in these states. We know which strains have been found in which state but we do not know the proportion," John told IndiaSpend.
He said that the union health ministry's Indian Council of Medical Research (ICMR), India's nodal health body for the Covid-19 pandemic, should have published comorbidity-related data at the national level, or at least asked all states to provide this information.
IndiaSpend has asked ICMR for comment over email on June 23 on whether they had the national-level figures on the share of death without comorbidity during the first wave and the second, the state-wise share for the same and whether it was possible for ICMR to ask the state to provide data in a uniform way. But no response was received till the afternoon of June 27. We will update the article if they respond.
This lack of correlated data would hinder making any good use of the comorbidity-related statistics from the three states at present, Partha P. Majumdar, a distinguished professor at the National Institute of Biomedical Genomics (NIBG), Kalyani, said. "[To] move ahead from here, we will need to access data on some other related aspects," said Majumdar, who is also national science chair, Government of India. "For example, we know that the Delta strain spreads very fast but there is no evidence yet to say if the variant is also more deadly."
To assess if the Delta variant has any role in higher share of death without comorbidity in West Bengal, statistics related to the proportion of the variants in Tamil Nadu and Karnataka were required, said Majumdar. "But such data is not available in the published form," he said.
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