Transmission Dynamics and Estimation of Basic Reproduction Number (R0) from Early Outbreak of Novel Coronavirus (COVID-19) in India

Abstract

Novel coronavirus (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an epidemic declared by the World Health Organization (WHO). Till now in June 13, 2020, the total COVID-19 cases in different countries around the world are 77,56,905 with 4,28,576 deaths and 3,974,422 recovered. The virus has taken spread in India as well, whereas of June 13, 2020, 3,09,603 cases are confirmed with 8,890 deaths and 1,54,330 recovery. It this situation, it is vital to know the potential danger posed by the pandemic and the epidemic trajectory. In this paper, the basic reproduction number (R0) of COVID-19 from the early epidemic data in India is estimated. The course of the pandemic in India as well as the worst affected seven states in India, namely Maharashtra, Tamil Nadu, Delhi, Gujarat, Uttar Pradesh, Rajasthan and West Bengal is also analyzed. The early outbreak data from the Ministry of Health and Family Welfare (MoHFW), Government of India, are collected for the analysis. The two R packages ‘R0’ and ‘earlyR’ to estimate the basic reproduction number are used. An attempt is also made to forecast near-future incidence cases based on statistical methods. The results show that R0 varies from 1.53 to 3.25 accounting to different methodologies and serial intervals adopted, whereas WHO estimations are from 2 to 2.5. Due to effect of lockdown, the time-dependent reproduction number has reduced to near about 1.22. It is predicted that by July 15, cumulative number of COVID-19 cases may reach around 1.2 million if the current effective reproduction number remains same over the next one month. Finally, it can be concluded that in the coming months, the novel coronavirus will pose a severe challenge to the Indian healthcare system. Thus, it is necessary to predict how the virus may spread so that the healthcare system may be prepared in advance. The time-dependent reproduction number shows the positive effect of lockdown, as this number has gone down.