Since the emergence of the coronavirus disease 2019 (COVID-19) in December, 155 countries have reported cases of COVID-19, including sustained community transmission in several countries, such as China, Italy, and Iran. As of March 21, 2020, there have been 275 434 cases confirmed globally, including 11 399 deaths.1 While the situation in China has improved, many countries continue to struggle with escalating case numbers and strained health care systems that are threatened to be overwhelmed by the pandemic.
One of the World Health Organization’s strategic priorities is to limit human-to-human transmission, including secondary infections among health care workers, which was a key feature of the severe acute respiratory syndrome (SARS) epidemic in 2003 and accounted for one-fifth of all cases globally. Although SARS and COVID-19 are both transmitted by droplets, it is now clear that the infectivity and extent of spread of COVID-19 will far exceed that of SARS.