COVID-19(7) Coronavirus disease 2019(6) coronavirus(6) SARS-CoV-2(5) Patient(4) patients(4) country(4) acute respiratory syndrome(4) coronavirus disease(4) Vaccine(4) pandemic(4) severe acute respiratory syndrome coronavirus 2(3) Chemotherapy(3) SARS-CoV-2 vaccination(2) life(2) median(2) Italian(2) sequenced(2) mutations(2) cellular response(2) Regulation(2) chemotherapy cycle(2) used to evaluate(2) Surveillance(2) T-cell assessment.(2) BNT162b2 vaccine(2) chronic lymphocytic leukemia(2) Novel coronavirus(2) disease(2) healthy control(2)