Contributing to research themes:
B cell chronic lymphocytic leukemia (CLL) is the most common subtype of adult leukemia and is associated with profound secondary immunodeficiency. SARS-CoV-2 infection has been a significant cause of morbidity and mortality (Mato et al., 2020; Pagano et al., 2021), and immunological responses against SARS-CoV-2 vaccines are impaired (Fendler et al., 2021) in patients with CLL. In particular, reduced rates of seroconversion and antibody titer have been reported (Parry et al., 2021; Greenberger et al., 2021; Herishanu et al., 2022) and associate with reduced serum immunoglobulin level or use of medication such as Bruton tyrosine kinase inhibitors or anti-CD20 antibodies (Parry et al., 2021; Herishanu et al., 2022). However, questions regarding optimal immune protection remain unresolved, and these include the potential for additional vaccine doses to increase seroconversion rate, potential humoral and cellular immune protection against Omicron, and the impact of vaccine delivery on breakthrough infection rate and clinical outcome.