COVID-19 Clinical Outcomes and Vaccine Efficacy among Patients with Hematologic Malignancies

The coronavirus disease 2019 (COVID-19) pandemic places the treating hematologist in a quandary: how best to protect patients with hematologic malignancies from potentially deadly COVID-19 infection while also providing the best therapy for their disease and maximizing opportunities for cure. Cancer patients as a whole trend toward more severe infection and increased mortality from COVID-19 infection. This burden, however, is not equally distributed among all cancer patients and outcomes are particularly poor in those with hematologic malignancies [1]. Lymphodepleting treatments have a profound effect on COVID outcomes; we have recently reported that despite proper and even prolonged quarantine after asymptomatic positive screening test for COVID-19, the initiation of rituximab-based chemotherapy resulted in a delayed respiratory failure in three lymphoma patients [2]. In addition to more severe infection and increased mortality, immunocompromised patients shed virus and remain infectious for far longer than the general population, frequently for several months or longer [3,4]. Finally, to add insult to injury, patients with hematologic malignancies have worse clinical and laboratory responses to vaccines, compromising their ability to be protected against infection and severe disease [5,6]. Prolonged viral shedding, decreased ability to form a durable immune response to vaccination or infection, and subsequent increased probability for severe infection pose a problem for those needing treatment due to progressive disease. Treatment delays in some cases can reduce cure fractions and increase likelihood of disease-related complications. With these cases in mind, there is a need to identify those patients who are at greatest risk of severe infection and determine what steps can we take to minimize the morbidity and mortality associated with both COVID-19 and the hematologic malignancy.