Regional difference in the rate of spread of SARS-CoV-2

To the Editor—After the first case of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was reported in Wuhan, China, in December 2019, the total number of confirmed cases had risen to 1,800,000, globally, and the total number of deaths had exceeded 120,000 by April 15, 2020.1 During this period, vast epidemiological data were collected globally that can provide clues about how to address this pandemic. All of the data we analyzed were obtained from the World Health Organization.1 To assess the regional differences in the rate of spread, we prepared growth curves of the cumulative cases per 100,000 population in 16 countries by calculating the ratio between the total number of confirmed cases and the country’s population. [...]we propose that the limited number of PCR tests conducted is the main reason for the small number of confirmed cases and that the underdeveloped private practice system and strict government policy have prevented people from undergoing PCR testing in Japan.2 Although the low cumulative incidence per 100,000 population in Japan is striking, the incidence rates of the other Asian countries are also much lower than those of European and North American countries.