Use case load of 14 days earlier to get death rate: researchers

The death rate, also referred to as case fatality ratio (CFR), is calculated by dividing the total number of deaths with the total number of infections, and expressed as a percentage.

Written by Anuradha Mascarenhas

Pune | June 17, 2020 02:19 AM IST

4 min read

The researchers say that an internationally accepted time lag to be used for this is 14 days. (File Photo)

Arguing that the commonly used method for calculating the death rate of Covid-19 is not truly representative of the actual situation, a group of researchers from Mumbai and Thiruvananthapuram has suggested that the actual mortality could be even two times higher.

The death rate, also referred to as case fatality ratio (CFR), is calculated by dividing the total number of deaths with the total number of infections, and expressed as a percentage. For example, India’s CFR on Monday, with 9,990 deaths and 3.43 lakh cases, can be calculated to be 2.91 per cent.

But the researchers from International Institute of Population Sciences (IIPS), Mumbai, a deemed university and autonomous organisation under the Ministry of Health and Family Welfare, and Thiruvananthapurm-based Centre for Development Studies (CDS), a research centre backed by Kerala government and Indian Council of Social Science Research, argue that this is erroneous.

In a study now available for review, the researchers point out that deaths today are of people who got infected a few days earlier. Also, even if infections suddenly stopped today, deaths would continue for the next few days, the victims being people who are already infected or are in hospitals. Therefore, they argue, the denominator to be used in calculating CFR should not be current caseload, but an earlier caseload.

The researchers say that an internationally accepted time lag to be used for this is 14 days.

According to them, the number of dead today need to be measured against the caseload of 14 days earlier to arrive at a more accurate picture of the mortality. If that yardstick is applied, the current CFR in India jumps to 5.03 per cent.

For the study, data until May 14 had been used, and in that case the CFR rose from 3.23 per cent to 8.01 per cent.

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“Case fatality ratio is illusive in that the same with 14 days delay for India is at least two times higher,” Sanjay Mohanty, professor at the Department of Fertility Studies at IIPS Mumbai, said. He also pointed to a study in ‘The Lancet’ journal which had used the same method in March to calculate CFRs of different countries.

Another set of scientists and epidemiologists considers the current CFR to be erroneous for an entirely different reason. These scientists insist that the mortality of a disease must be assessed against the total number of people who have been infected, and not just those who have tested positive. But since a large number of infected people are believed to be asymptomatic, and not everyone is being tested, the total number of infections is not available, certainly not when the epidemic is still unfolding.

At the end of the epidemic, however, a reliable estimate can be arrived at, and this estimate would be much higher that the number of confirmed infections that is currently being used for calculating CFR. In such a scenario, the CFR is expected to be well below 1 per cent, they argue.

The researchers from IIPS and CDS also claim in their study that just a 0.5 per cent of community transmission of the disease could lead to so many deaths in the 47-65 year age group that it would have the effect of reducing India’s life expectancy by one year.

Anuradha Mascarenhas

Anuradha Mascarenhas is a Senior Editor at The Indian Express, based in Pune. With a career spanning three decades, she is one of the most respected voices in Indian journalism regarding healthcare, science and environment and research developments. She also takes a keen interest in covering women's issues . Anuradha has won several awards including the Press Council of India's national award for excellence in journalism under the gender based reporting category in 2019 and the Laadli Media award (gender sensitivity -2024). A recipient of the Lokmat journalism award (gender category-2022), she was also shortlisted for the RedInk awards for excellence in journalism-2021. Her debut book At The Wheel Of Research, an exclusive biography of Dr Soumya Swaminathan the inaugural chief scientist of World Health Organisation was also nominated in the Popular Choice Category of JK Paper AUTHER awards. She has also secured competitive fellowships including the Laadli Media Fellowship (2022), the Survivors Against TB – New Research in TB Media Fellowship (2023) and is part of the prestigious 2025 India Cohort of the WomenLift Health Leadership Journey.” Professional Background Education: A gold medalist in Communication and Journalism from Savitribai Phule Pune University and a Master’s degree in Literature. Author: She authored the biography At The Wheel Of Research, which chronicles the life and work of Dr. Soumya Swaminathan, the former Chief Scientist at the WHO. Key Focus: She combines scientific accuracy with storytelling, translating complex medical research into compelling public and human-interest narratives. Recent Notable Articles (Late 2025) 1. Cancer & Specialized Medical Care "Tata Memorial finds way to kill drug-resistant cancer cells" (Nov 26, 2025): Reporting on a breakthrough for triple-negative breast cancer, one of the most aggressive forms of the disease. ``Discipline, diet and purpose; How a 97-year-old professor defies ageing'' (Nov 15, 2025) Report about Prof Gururaj Mutalik, the first Head of Department at Pune's B J Government Medical College who at 97 credits his longevity to healthy habits and a strong sense of purpose. 2. Environmental Health (The "Breathless Pune" Series) "Long-term exposure even to 'moderate' air leads to chronic heart, lung, kidney issues" (Nov 26, 2025): Part of an investigative series highlighting that even "safe" pollution levels are damaging to vital organs. "For every 10 µg/m3 increase in PM2.5 level, there was 6-8% jump in medicine sales" (Nov 23, 2025): Using commercial data to prove the direct link between air quality and respiratory illnesses in Pune. 3. Lifestyle & Wellness News "They didn't let cancer, diabetes and heart disease stop them from travelling" (Dec 22, 2025): A collaborative piece featuring survivors who share practical tips for traveling with chronic conditions. ``At 17, his BP shot up to 200/120 mmHG; Lancet study flags why child and teen hypertension doubled between 2000 and 2020'' (Nov 12,2025)--A report that focusses on 17-year-old-boy's hypertensive crisis and reflects the rising global trend of high blood pressure among children and adolescents. 4. Scientific Recognition & Infrastructure "For promoting sci-comm, gender diversity: IUCAA woman prof highlighted in Nature" (Nov 25, 2025): Covering the global recognition of Indian women scientists in gender studies and physics. ``Pune researchers find a spiral galaxy like the Milky Way from early universe'' (December 3, 2025)- A report on how Indian researchers discovered a massive galaxy that existed when the universe was just 1.5 billion years old , one of the earliest to have been observed so far. Signature Beat: Health, Science & Women in Leadership Anuradha is known for her COVID-19 reportage, where she was one of the first journalists to provide detailed insights into the Covishield and Covaxin trials. She has a dedicated interest in gender diversity in health and science, often profiling women researchers who are breaking the "leaky pipeline" in STEM fields. Her writing style is scrupulous, often featuring interviews with top-tier scientists and health experts from various institutions X (Twitter): @runaanu ... Read More

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