Observations of the global epidemiology of COVID-19 from the prepandemic period using web-based surveillance: a cross-sectional analysis

Study noted among 1st case reported from each of 99 affected countries outside mainland China, 75 (76%) had recent travel to affected countries; 60 (61%) had travelled to China, Italy, or Iran. Among 762 early cases, median age was 51 years and 25 (3%) were children <18 years.

The Lancet Infectious Diseases