Patients with hematologic malignancies have an increased risk of severe COVID-19 infection. Vaccination against COVID-19 is especially important in these patients, but whether they develop immune response following vaccination is unknown. We studied serologic responses to the BNT162b2 vaccine in this population. A lower proportion of patients were seropositive following vaccination (75%) than in a comparison group (99%), p<0.001, and median antibody titers in patients were lower (90 AU/ml, IQR 12.4-185.5 and 173 AU/ml, IQR 133-232, respectively, p<0.001). Older age, higher LDH, and number of treatment lines correlated with lower seropositivity likelihood and antibody titers, while absolute lymphocyte count, globulin level, and time from last treatment to vaccination, correlated with higher seropositivity likelihood and antibody titers. CLL patients had the lowest seropositivity rate followed by indolent lymphoma. Patients recently treated with chemo-immunotherapy, anti CD20 antibodies, BCL2, BTK or JAK2 inhibitors had significantly less seropositive responses and lower median antibody titers (29%, 1.9 AU/ml, IQR 1.9-12; 0%, 1.9 AU/ml, IQR 1.9-1.9; 25%, 1.9 AU/ml, IQR 1.9-25; 40%, 1.9 AU/ml, IQR 1.9-92.8; 42%, 10.9 AU/ml, IQR 5.7-66.4 respectively, p<0.001). Serological response to BNT162b2 vaccine in patients with hematologic malignancies is considerably impaired, and they could remain at risk for severe COVID-19 infection and death. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.

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