Switzerland began a national lockdown on March 16 , 2020, in response to the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed the prevalence of SARS-CoV-2 infection among patients admitted to 4 hospitals in the canton of Zurich, Switzerland, in April 2020 . These 4 acute care hospitals screened 2,807 patients, including 2,278 (81.2 %) who did not have symptoms of coronavirus disease (COVID-19). Overall , 529 (18.8 %) persons had> 1 symptom of COVID-19, of whom 60 (11.3 %) tested positive for SARS-CoV-2 . Eight asymptomatic persons (0.4 %) also tested positive for SARS-CoV-2 . Our findings indicate that screening on the basis of COVID-19 symptoms, regardless of clinical suspicion, can identify most SARS-CoV-2-positive persons in a low-prevalence setting.