Among the 54 symptomatic patients with CLL/Ly, 37 were on active treatment at the time of vaccination; 4 patients were receiving BTKi with Rituximab, 16 under monotherapy with a Bruton’s Tyrosine Kinase (BTK) inhibitor, 14 patients under treatment with a Rituximab-based regimen, and 3 patients receiving a chemotherapy-based regimen only. This evidence concerns the gene BTK and B-cell chronic lymphocytic leukemia.