Cellular Immune Responses to BNT162b2 mRNA COVID-19 Vaccine in Patients with Chronic Lymphocytic Leukemia

Background: Patients with chronic lymphocytic leukemia (CLL) are known to have a suboptimal immune response of both humoral and cellular arms. Recently, a BNT162b2 mRNA COVID-19 vaccine was introduced with a high efficacy of 95% in immunocompetent individuals. Approximately half of the patients with CLL fail to mount a humoral response to the vaccine, as detected by anti-spike antibodies. Currently, there is no data available regarding T-cell immune responses following the vaccine of these patients.