In December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused an outbreak of coronavirus disease 2019 (COVID-19) (Wu et al., 2020). Person-to-person transmission of SARS-CoV-2 has been confirmed, and individuals with asymptomatic infections have been identified as potential infection sources (Chan et al., 2020; Rothe et al., 2020). To date, SARS-CoV-2 has spread to almost all countries worldwide, and the number of confirmed cases and deaths has been growing rapidly due to the high rate of infectivity (R0).
