The Peak of COVID-19 in India (Preprint)

BACKGROUND Following the USA, India ranks the second position in the world for COVID-19 cases with the highest number of daily confirmed cases since September 2020. The peak of daily confirmed cases is the most warranted feature for understanding the epidemiological stage of COVID-19 disease in India. OBJECTIVE The objectives of the study are to analyse the growth rates of the confirmed cases of COVID-19 in India, and to provide an expected count of the peak of confirmed cases and a possible track of confirmed cases. METHODS Exponential model was applied to estimate the growth rates of daily confirmed cases. The estimated growth rates were used for calculating the doubling time. The Lotka-Euler method was applied to calculate the effective reproduction rate. SARIMA model was developed for the growth rates to predict daily confirmed cases. RESULTS Results show the best fit of the exponential model over the daily confirmed cases. The growth rates estimated from the exponential model shows an unsteady, modest decline. Doubling time shows a linear increase. The effective reproduction rate declined from 3.6 persons in the third week of March 2020 to 1.14 persons at the end of August 2020 and 1.10 at the end of September 2020. The diagnosis of the developed SARIMA model confirmed no trends in the residuals, no outliers, and nearly constant variance. The forecast suggests the peak value of daily confirmed cases wavers around 104,500 counts in the third week of September 2020. The cumulative COVID-19 cases account for approximately 105 lakhs at the end of December 2020. CONCLUSIONS The exponential model unravels a shift and a modest decline in the growth of daily confirmed cases. The trends in R(t) show analogous to the trends in growth rates of daily confirmed cases. The study shows that the SARIMA model is suitable for projecting daily confirmed cases. The results shed light on the understanding of the trends and epidemiological stage of COVID-19 disease, in the cognisance of the peak. This study based on moments of the distribution of the daily confirmed cases of COVID-19 disease unravels the uncertainty about the peak and curvature of COVID-19 disease. The prediction made based on our calculations is adjoining to the real-time peak value of daily confirmed cases in India and successfully explores the epidemiological stage of COVID-19 disease in India.