Much has been learned about coronavirus disease 2019 (COVID-19) in the past 4 months, but still much remains unknown. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is well characterized but how widely it has spread throughout the population is not known, nor is it known why some individuals who are infected with the virus do not develop symptoms, whereas other individuals develop serious COVID-19 disease with a high mortality rate. COVID-19 has had a devastating effect on the world, bringing normal activities and the economy to a near halt.