Since its initial outbreak in China, in December, 2019, COVID-19 has spread rapidly across the globe. At the time of writing, on April 29, 2020, infections had been confirmed in more than 200 countries and regions and 3,018,681 infections and 207,973 deaths had been recorded. In Japan, the first confirmed case of SARS-CoV-2 infection was reported on January 16, 2020, since when, the number of domestic infections and the death toll have reached 13,852 and 389, respectively, representing exponential increases. Moreover, both domestically and internationally, the shortage of medical resources and the spread of infection among medical personnel, caused by nosocomial transmissions have become problematic. The pathology of COVID-19, including the exact infection route, remains largely unknown. Given the unavailability of an effective cure and vaccine, people are required to respond to this adversity without becoming complacent. The global efforts against the COVID-19 pandemic are ongoing endeavors, far from over. New epidemiological data and clinical findings are emerging on a daily basis, making it critical to always refer to the latest information.