COVID-19 Among Patients with Hematological Malignancies: Experience from a Tertiary Center Showing Lower Than Expected Mortality and Establishing the Safety of in-Hospital Patient Care during the Pandemic

Previous studies and meta-analyses addressing COVID-19 in patients with hematological malignancies (HM) have reported dramatically high mortality rates of up to 34% [Vigenthira 2020, Garcia-Suarez 2020, Sharafeldin 2021]. These studies, however, were strongly biased towards hospitalized patients, and poorly represented patients who experienced a milder course of COVID-19, not requiring hospitalization. Jerusalem and its metropolitan area, comprising of over 1.3 million inhabitants, was the epicenter of Israel's COVID-19 crisis, with over 200,000 cases. Hadassah Medical Center, one of only two tertiary centers serving this multi-ethnic population, houses a Hematology Department that includes inpatient services, a hematopoietic stem cell transplant (HSCT) center, day care services and in-campus outpatient clinics. From February 20 th, 2020, we tracked patients with confirmed COVID-19 reporting to their treating hematologists while being hospitalized due to COVID-19, at routine visits to the hematology services, or remotely via phone or email communication. This assured the representation of COVID-19 cases of various clinical severities. Data were collected retrospectively and included demographics, comorbidities, hematological diagnoses and treatments, course of COVID-19 and, importantly, source of infection. Univariate and multivariate analyses were used to assess association between prognostic factors and outcomes including hospitalization, severe COVID-19 (per updated WHO criteria) and critical COVID-19, defined as a composite of ICU admission and mortality. Almost all the patients in this series were diagnosed prior to their vaccination. To the best of our knowledge, this is the largest single center series of HM patients with COVID-19 reported to date. Our series included 183 patients. Median age was 62.5 years, 57% were men, and 72% had at least one comorbidity. The most frequent hematological diagnoses were indolent lymphoma and CLL (40%), aggressive lymphoma (20%) and multiple myeloma (19%). At the time of COVID-19 diagnosis, 41% of the patients were receiving systemic anti-neoplastic treatment (excluding TKIs for CML and hydroxyurea for MPN), and 16% had undergone a previous allogeneic or autologous HSCT. Overall mortality, severe COVID-19, and hospitalization rates in the entire group were 9.8%, 14.2% and 32%, respectively, remarkably lower than in previous reports. Of the patients not receiving anti-neoplastic treatment, mortality and severe COVID