A nationwide cross-sectional study using a web-based questionnaire survey of the duration of isolation of COVID-19 inpatients with cancer at Japanese cancer centers

There is no clear consensus regarding the optimal isolation duration for immunocompromised patients with coronavirus disease 2019 (COVID-19). Therefore, we conducted a questionnaire survey at eight Japanese cancer centers to investigate the practices of infectious disease specialists regarding the duration of isolation for COVID-19 inpatients with cancer. For asymptomatic to severely ill COVID-19 inpatients without severe immunodeficiency, four centers reported at least 10 days of isolation without testing, and two reported at least 20 days. Two centers incorporated polymerase chain reaction (PCR) as a criterion for terminating the isolation of inpatients without severe immunodeficiency. For severely immunocompromised COVID-19 inpatients, at least 20 days of isolation were required in seven facilities, regardless of illness severity. Additionally, seven centers had implemented Ct or antigen quantification test values as criteria for de-isolating severely immunocompromised inpatients. No cases caused nosocomial outbreaks after isolation was terminated based on each facility's criteria for isolation termination. Thus, cancer patients required longer isolation periods than the general population in most facilities, and for those with severe immunodeficiency, the isolation periods were longer and more tightly controlled with tests.