Decoding India's Low Covid-19 Case Fatality Rate

ABSTRACT

India's case fatality rate (CFR) under Covid-19 is strikingly low, around 1.7% at the time of writing. The world average rate is far higher. Several observers have noted that this difference is at least partly due to India's younger age distribution. We use age-specific fatality rates from 17 comparison countries, coupled with India's distribution of Covid-19 cases, to “predict” India's CFR. In most cases, those predictions yield even lower numbers, suggesting that India's CFR is, if anything, too high rather than too low. We supplement the analysis with a decomposition exercise, and we additionally account for time lags between case incidence and death for a more relevant perspective under a growing pandemic. Our exercise underscores the importance of careful measurement and interpretation of the data, and emphasises the dangers of a misplaced complacency that could arise from an exclusive concern with aggregate statistics such as the CFR.

KEYWORDS:

• Covid-19
• Case fatality rate
• Demographics
• Public health
• Cross-country comparisons
• Age-specific mortality

Acknowledgments

We thank Dean Spears for useful comments, and Vrinda Anand for helpful assistance.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Bhramar Mukherjee, in private communication, suggests a nationwide under-reporting factor of the order of 15–25, implying a current infected population of 30–50 million. See Bhattacharyya et al. (2020) for more details on the calculation of the under-reporting factor for India.

2 There are many reasons why the absolute values of CFRs have no obvious and natural meaning, some of which will play an unavoidable role in this paper.

3 The Hindustan Times, July 26, 2020; https://www.hindustantimes.com/india-news/pm-narendra-modi-s-67th-mann-ki-baat-address-to-nation-highlights/story-bXhnWiU1WElwNLFp0mpWRJ.html.

4 There are, of course, several other reasons for the CFR to vary across countries. Countries with higher testing rates will generally have lower CFRs — spotting more cases at an earlier and presumably milder stage. Moreover, CFRs will tend to trend down over time within the same country, as testing improves. Actually, India is pretty low on the world testing scale as measured by per-capita tests, so this logic suggests that its CFR should be higher, not lower. There are other ancillary issues, such as obvious caveats associated with using data from multiple sources, such as definitional differences in what constitutes a – “Covid-19 death.” There is also the question of under-reporting (Pundir 2020; Thapar 2020; Chatterjee 2020), though this will affect both numerator and denominator in the CFR.

5 The remaining seven countries are Australia, Canada, Denmark, Finland, Israel, Mexico and Norway. Including them does not affect the analysis but lengthens the tables without much added insight.

6 It is possible that relative to the comparison countries, the old remain at home in India during their illness, and Covid deaths as well as cases are disproportionately undercounted among them.

7 The Italian comparison exhibits some contrast to Mukhopadhyay's (2020) analysis. He undertakes a similar exercise as in Table 2 using Italian data, and reports that: “[B]y multiplying Italy's age-specific CFR … to the age-specific number of cases in India, [we find that] [t]he estimated numbers of deaths that should have occurred, if the age-specific death rates of Italy were to prevail in India, is 535. The official number of deaths in India as of April 30 was actually twice that number, at 1074.” We go some way towards a resolution of this difference in Section 4, though the disparity is still puzzling.

8 Based on a study of Chinese data by Yang et al. (2020), Wilson et al. (2020) conclude that “… a median of 13 days passed from pneumonia confirmation to death…”

Additional information

Funding

Ray acknowledges research support from the National Science Foundation under Grant No. SES-1851758.

Notes on contributors

Minu Philip

Minu Philip is a doctoral student in Economics at New York University. She completed her BA. (Hons.) in Economics from St. Stephen's College, Delhi and M.Sc. in Economics from Indira Gandhi Institute of Development Research, Mumbai. Her research interests include Applied Microeconomics and Development Economics.

Debraj Ray

Debraj Ray is Julius Silver Professor in the Faculty of Arts and Science and Professor of Economics at New York University. He received his BA from the University of Calcutta and his PhD in 1983 from Cornell University. He is a Fellow of the Econometric Society, a Guggenheim Fellow, and a Fellow of the American Academy of Arts and Sciences. He is on the Council of the Game Theory Society and the Board of Directors of the Bureau for Research in the Economic Analysis of Development (BREAD). He received the Dean's Award for Distinguished Teaching at Stanford and the Gittner Award for Teaching Excellence at Boston University. He holds an honorary degree from the University of Oslo, and was a Co-Editor of the American Economic Review between 2011 and 2020.

S. Subramanian

S. Subramanian is a former professor from the Madras Institute of Development Studies and a former National Fellow of the Indian Council of Social Science Research. He has research interests in aspects of social and economic measurement, collective choice theory, and development economics. He is a Fellow of the Human Development and Capability Association.