Prevalence and Clinical Characterization of Cancer Patients with Asymptomatic SARS CoV 2 Infection History

•We retrospectively studied the prevalence and clinical characterization of cancer patients with asymptomatic SARS-CoV-2 infection history in the only cancer hospital in Wuhan.•Serosurvey of SARS-CoV-2 among hospital visitors from two hospitals, one at the epicenter in Wuhan, and one outside the epicenter, in Guangzhou.•Cancer patients are more likely to develop asymptomatic COVID-19 infection than persons with similar exposure history.•Transmissibility of asymptomatic cases is relatively low, even in vulnerable populations such as cancer patients.