Estimating the wave 1 and wave 2 infection fatality rates from SARS-CoV-2 in India

Springer Science and Business Media LLC - Tập 14 - Trang 1-7 - 2021
Soumik Purkayastha1, Ritoban Kundu2, Ritwik Bhaduri2, Daniel Barker1, Michael Kleinsasser1, Debashree Ray3,4, Bhramar Mukherjee1,5,6
1Department of Biostatistics, University of Michigan, Ann Arbor, USA
2Indian Statistical Institute, Kolkata, India
3Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA;
4Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
5Center for Precision Health Data Science, University of Michigan, Ann Arbor, USA
6Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, USA

Tóm tắt

There has been much discussion and debate around the underreporting of COVID-19 infections and deaths in India. In this short report we first estimate the underreporting factor for infections from publicly available data released by the Indian Council of Medical Research on reported number of cases and national seroprevalence surveys. We then use a compartmental epidemiologic model to estimate the undetected number of infections and deaths, yielding estimates of the corresponding underreporting factors. We compare the serosurvey based ad hoc estimate of the infection fatality rate (IFR) with the model-based estimate. Since the first and second waves in India are intrinsically different in nature, we carry out this exercise in two periods: the first wave (April 1, 2020–January 31, 2021) and part of the second wave (February 1, 2021–May 15, 2021). The latest national seroprevalence estimate is from January 2021, and thus only relevant to our wave 1 calculations. Both wave 1 and wave 2 estimates qualitatively show that there is a large degree of “covert infections” in India, with model-based estimated underreporting factor for infections as 11.11 (95% credible interval (CrI) 10.71–11.47) and for deaths as 3.56 (95% CrI 3.48–3.64) for wave 1. For wave 2, underreporting factor for infections escalate to 26.77 (95% CrI 24.26–28.81) and to 5.77 (95% CrI 5.34–6.15) for deaths. If we rely on only reported deaths, the IFR estimate is 0.13% for wave 1 and 0.03% for part of wave 2. Taking underreporting of deaths into account, the IFR estimate is 0.46% for wave 1 and 0.18% for wave 2 (till May 15). Combining waves 1 and 2, as of May 15, while India reported a total of nearly 25 million cases and 270 thousand deaths, the estimated number of infections and deaths stand at 491 million (36% of the population) and 1.21 million respectively, yielding an estimated (combined) infection fatality rate of 0.25%. There is considerable variation in these estimates across Indian states. Up to date seroprevalence studies and mortality data are needed to validate these model-based estimates.

Tài liệu tham khảo

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