Characterization of the Second Wave of COVID-19 in India

Abstract

AbstractThe second wave of COVID-19, which began around 11 February 2021, has hit India very hard with the daily cases reaching nearly triple the first peak value as on April 19, 2021. The epidemic evolution in India is quite complex due to regional inhomogeneities and the spread of several coronavirus mutants. In this paper, we characterize the virus spread in the ongoing second wave in India and its states until April 19, 2021, and also study the dynamical evolution of the epidemic from the beginning of the outbreak. Variations in the effective reproduction number (Rt) are taken as quantifiable measures of the virus transmissibility. Rt value for every state, including those with large rural populations, has value greater than the self-sustaining threshold of 1. An exponential fit on recent data also shows that the infection rate is much higher than the first wave. Subsequently, characteristics of the COVID-19 spread are analyzed regionwise, by estimating test positivity rates (TPRs) and case fatality rates (CFRs). Very high TPR values for several states present an alarming situation. CFR values are lower than those in the first wave but recently showing signs of increase as healthcare systems become over-stretched with the surge in infections. Preliminary estimates with a classical epidemiological model suggest that the peak for the second wave could occur around mid-May 2021 with daily count exceeding 0.4 million. The study strongly suggests that an effective administrative intervention is needed to arrest the rapid growth of the epidemic.