Antibody response to COVID-19 vaccination in patients with lymphoma.

Patients with lymphoma are at increased risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); therefore, evaluation of SARS-CoV-2 vaccination efficacy is essential. We conducted a prospective observational study to monitor the antibody response in 500 patients with lymphoma after SARS-CoV-2 vaccination. Antibody levels increased in a stepwise manner after the first and second dose of the vaccine. After completion of the two-dose series, anti-S antibody was negative in 109 patients (21.8%), and below clinically protective levels (anti-S ≥ 264 U/mL) in 236 patients (47.2%). The median anti-S titers at 0-6 months, 7-12 months, 13-24 months, and 24 months after treatment completion were 0.4 U/mL, 3.8 U/mL, 270 U/mL, and 650 U/mL, respectively. Multivariate analysis showed that receiving the vaccine < 6 months since completing treatment, white blood cell count < 5050/μL, percentage of CD19 + cells < 10%, CD4 + cells < 27%, immunoglobulin (Ig) A < 195 mg/dL, IgM < 50 mg/dL, serum soluble interleukin 2 receptor > 600 U/mL, and presence of lymphoma cells in the peripheral blood were significantly correlated with anti-S < 264 U/mL. Lymphoma patients had variably impaired antibody response to the SARS-CoV-2 vaccine. We identified various factors to predict COVID-19 vaccine effectiveness in lymphoma patients that may help tailoring possible vaccine boosters.