Asymptomatic carriers unknowingly spread COVID-19 in Asia, reports sayA multicenter study published yesterday in Travel Medicine and Infectious Disease shows that 60% of asymptomatic (symptom-free) COVID-19 patients in Sichuan province, China, were diagnosed as having pneumonia on their first computed tomography (CT) scan.The study involved 100 asymptomatic and 411 symptomatic coronavirus patients in hospitals in 21 cities and 47 counties or districts from Jan 25 to Feb 20.The researchers also found that patients without symptoms were younger and came from higher-altitude areas with less resident mobility and more defined epidemiologic history than patients with symptoms but had similar rates of underlying conditions.Of initially