Globally, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has affected more than 120 million individuals and caused 2.7 million deaths (Roser et al., 2021). As of 23 March 2021, there have been 457,754 cases and 8861 deaths in Japan (Ministry of Health, Labour and Welfare, 2021), which is lower than the number of cases and deaths reported in other countries with outbreaks of COVID-19 (Roser et al., 2021).