Understanding the epidemiology of COVID-19

COVID-19 caused by SARS-CoV-2 was reported in December, 2019 in Wuhan city of Hubei province, China, in people who had visited seafood market. Its symptoms were similar to pneumonia but its infectivity was very high. The main modes of transmission of SARS-CoV-2 were identified as spread by nasal droplets and oral-fecal route and COVID-19 was found to be infectious in incubation and asymptomatic period. Hence, by the time real potential of its pathogenicity was realized, it had spread to many regions of China, other Asian countries, European countries, United States etc. and by April 20, 2020, it had spread to 185 countries all over the world. By this time, China had contained the virus, due to strict social distancing measures, and there was decline in the number of positive cases but in many other countries, especially U.S. and European countries, the cases continued to rise. United States showed the sharpest rise in COVID-19 cases in April, 2020 and also reported the highest number of deaths from the disease. As most of the countries are facing first-wave of COVID-19 by April, 2020, there are fears of second-wave of COVID-19 as China plans to relax social distancing norms to resume business, other work etc. to combat economic losses. DOI: http://dx.doi.org/10.5281/zenodo.3822115