We describe a case of coronavirus disease 2019 (COVID-19) in a patient with mixed cellularity classical Hodgkin lymphoma (cHL) undergoing brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A+AVD) therapy . A 43-year-old man presented to our hospital with a complaint of fever, for which he was diagnosed with COVID-19 after a positive polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and antiviral therapy with favipiravir and ciclesonide was started subsequently . The fever persisted for the first few days of treatment, but his respiratory status was stable, and he became asymptomatic and afebrile on day 9 . Although the PCR tests remained positive, he met the updated discharge criteria of the World Health Organization (WHO) on day 12 . However, his fever recurred, and his condition worsened on day 16 . A chest X-ray showed a new opacity . It is likely that favipiravir and ciclesonide treatment probably did not completely eliminate the virus in the patient, and therefore the infection persisted . We added remdesivir from day 21, and the improvement was remarkable . He was discharged on day 29 after two consecutive PCR test results were negative . PCR tests are not mandatory for the updated WHO discharge criteria . However, even after antiviral therapy, COVID-19 patients with hematologic malignancies may have prolonged active infection with impaired viral excretion . Depending on the background disease and comorbidities, there may be some patient populations for whom it is not appropriate to simply comply with the current discharge criteria . Therefore, more emphasis may be needed on PCR examinations.