Chennai saw massive rise in overall deaths during second wave, shows new study
The city saw a 41% increase in overall mortality compared to pre-pandemic levels, with a higher death toll observed in poorer parts of the city during the second wave, shows a study published in Lancet Infectious Diseases
Deaths in Chennai peaked at levels 4.75 times higher during the brutal second wave of India’s Covid-19 outbreak compared to levels observed before the onset of the pandemic, shows a new study published in the journal Lancet Infectious Diseases.
The city saw a 41% increase in overall mortality compared to pre-pandemic levels, with a higher death toll observed in poorer parts of the city during the second wave, the study found.
The study, which analyses the “excess mortality” in the Tamil Nadu capital between March 24, 2020 and June 30, 2021, adds to a growing trove of evidence that seeks to uncover crucial data uncovering the actual toll of the pandemic.
“All-cause excess death” is a generalised term that refers to the total number of deaths occurring due to all causes during a crisis that is above and beyond what would have been expected under normal conditions.
To be sure, not all such excess deaths may be due to Covid-19, but during a pandemic, such major deviations in fatalities are likely to be either directly or indirectly caused by the outbreak and the stress it caused on a region’s health care system.
In the study titled “All-cause mortality during the Covid-19 pandemic in Chennai, India: an observational study”, released on Thursday, researchers analysed death registrations in Chennai in order to measure changes in fatality numbers through the pandemic.
The study was conducted by researchers from the Tamil Nadu government, Washington-based Centre for Disease Dynamics, Economics and Policy (CDDEP), University of California Berkeley, and Johns Hopkins University.
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The study used death registration data from Tamil Nadu’s Civil Registration System (CRS) and closely matched mortality estimates from India’s demographic survey-based Sample Registration System (SRS), the authors said.
“Between March 1, 2020 and June 30, 2021, 87,870 deaths were registered in areas of Chennai district represented by the 2011 census, exceeding expected deaths by 25,990,” the study said.
It means Chennai recorded 5.2 excess deaths registered per 1,000 residents since the start of the Covid-19 pandemic, marking a 41% increase in overall deaths through the period of study compared to the pre-pandemic average.
The researchers found that their estimates of excess mortality (5.2 deaths per 1,000 residents) in Chennai exceeded similar findings from higher-income settings such as in the United States, United Kingdom, Spain, Italy, etc (where it ranged from 1.6-2.1 excess deaths per 1,000) despite India’s younger age distribution – a factor that many had hoped would provide relative protection to India against a disease like Covid-19 that is statistically known to be disproportionately fatal to the elderly.
The 41% increase, however, was far from being equally spread through the pandemic, the researchers found.
They divided their analysis into three periods of interest – the first four weeks of India’s first lockdown (March 24 to April 20, 2020), a four-month period including the first wave (May 1 to August 31, 2020), and a four-month period including the second wave in Chennai (March 1 to June 30, 2021).
Most excess deaths occurred during the second wave when mortality peaked at levels 4.75 times higher than pre-pandemic observations, the authors noted.
Different waves also targeted different socioeconomic levels differently, the researchers found. Through the overall pandemic period, “0.7% to 2.8% higher mortality was observed per 1 SD (standard deviation) increase in each measure of community socioeconomic deprivation”, they said.
“Communities with lower socioeconomic status had reductions in mortality during the early lockdown, but also had the greatest increases in mortality during the second wave. Therefore, such communities had a disproportionate burden of excess deaths overall,” the study noted.
“Differential access to care is more of an issue when the health care system is overwhelmed. That is likely the biggest contributor to more excess deaths among the poor,” said the study’s lead author, Dr Ramanan Laxminarayan, director of CDDEP.
“The enormous toll taken by Covid-19 on many countries is evident but poorly measured. In India, the high quality of deaths recording in Chennai made possible a careful study of the effect of Covid on all-cause mortality. There are very few large-scale studies examining all-cause mortality in low-income and middle-income countries (LMICs),” said Laxminarayan. “With new variants spreading rapidly, the pandemic wears on, and there is a greater need for understanding socioeconomic patterns for all-cause mortality, and dissimilarities between various settings to strengthen public health decision-making.”
Laxminarayan had previously published one of the world’s largest Covid-19 contact-tracing studies in 2020, which found that a tenth of all cases become “superspreaders” and account for 60% of new infections, while 70% of Covid patients do not pass on the disease to anyone else.
Previously, separate analysis conducted by several news organisations such as The Hindu, Scroll, The News Minute, Article 14, among others, have estimated the undercount factor for India’s states, cities and districts.
Such estimates have been arrived at for Andhra Pradesh, Assam, Gujarat, Himachal Pradesh, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Punjab, Tamil Nadu, Uttar Pradesh and West Bengal, among other states, and have shown a wide range of undercount factors - as little as 0.42 times in Kerala to 43 times in UP (based on data from 24 of the state’s 75 districts).
On August 21, an analysis of CRS data in Bihar by HT showed that there were at least 251,000 excess deaths in the state since the start of the pandemic, which is 48.6 times the official number of reported Covid-19 deaths (5,163) from the same time.
The figures in Bihar presented one of the largest deviations in excess mortality seen in any Indian state so far.