Current perspectives regarding SARS-CoV-2 vaccination in chronic lymphocytic leukemia

In immunocompetent people, the mRNA vaccines BNT162b2 and mRNA-1273 have been shown to be safe and effective against coronavirus disease of 2019 (COVID-19). However, results of cohort studies and meta-analyses have indicated that the degree of humoral response to SARS-CoV-2 vaccines in patients with chronic lymphocytic leukemia (CLL) appears to be lower than that observed in the general population. These inadequate responses are mainly related to the disease itself and to the immunosuppressive effect of therapies administered. In the specific context of CLL, enrolling patients with sub-optimal vaccine-response in pivotal vaccine trials could be considered as an appropriate approach to improve response to the COVID-19 vaccine. These clinical trials should also address the issues of regularity and timing of vaccine booster doses or re-vaccinations, especially in patients undergoing therapy with pathway-targeting agents and anti-CD20 monoclonal antibodies. However, since hypogammaglobulinemia is a serious consequence of CLL, patients who do not have a detectable antibody response should be natural candidates for preventive antibody therapy.