In late December 2019, a cluster of unexplained cases of viral pneumonia occurred in Wuhan, China.1 This initial cluster of patients with what soon became known as coronavirus disease 2019 (COVID-19) heralded the arrival of a new pandemic caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, close to 90 000 cases have occurred in more than 60 countries with approximately 3000 deaths. The World Health Organization (WHO) has declared these events a Public Health Emergency of International Concern.
It is expected that a COVID-19 vaccine will take 12 to 18 months to develop and manufacture, and even then it may not be effective. Therapeutics might be developed much more quickly, with clinical trials already under way, but it is too soon to know when such therapies might be available. There are still many uncertainties regarding COVID-19, including the number of asymptomatic or mildly symptomatic cases in China and other countries, the overall attack rate in the population, and the ultimate case-fatality rate in different countries around the world.