Estimating the Final Epidemic Size for COVID-19 Outbreak using Improved Epidemiological Models

Rajesh Ranjan

In order to have further insights into the spread of this epidemic, it is important to include the effects of social distancing. The basic reproduction number R 0 for SARS-CoV-2 can be as high as 4, indicating a very high transmission rate of the disease. Therefore, in the absence of any available treatment approved by medical authorities and World Health Organization (WHO), countries have taken an aggressive measure to control the epidemic. About one-third of the world population is currently under lockdown to arrest the spread of this highly infectious disease. Table 2 shows the list of a few geographical regions with their lockdown status. In the US, social distancing measures are enforced differently in different states and hence are reported separately for some key states most affected. The inclusion of Ohio is to show the disparity in the number of cases compared to a few other states which are most affected. Similarly, India is included to compare the number of cases when measures for social distancing were imposed.