Patients with CLL have similar high risk of death upon the omicron variant of COVID-19 as previously during the pandemic.

Previous studies have shown that patients with chronic lymphocytic leukemia (CLL) and coronavirus disease 2019 (COVID-19) have high mortality rates. The omicron variant has been reported to give milder disease in the general population, but outcomes of infections with the omicron variant among immunocompromised patients have not previously been reported. In a population-based cohort we assessed rates of hospitalizations, ICU-admissions, and 30-day all-cause mortality among all patients with CLL from Eastern Denmark testing positive for severe adult respiratory syndrome coronavirus 2 (SARS-CoV-2) in time periods before and after dominance of the omicron variant. Rates of hospitalizations and ICU-admissions declined significantly, whereas 30-day mortality remained as high as 23% in the period with dominance of the omicron sublineage BA.2 variant. Thus, patients with CLL in general and in particular those above 70 years of age with one or more comorbidities should be considered for closer monitoring and pre-emptive antiviral therapy upon a positive SARS-CoV-2 test. Key pointsO_LIThe omicron variant of COVID-19 leads to high fatality rates in CLL, despite milder disease in the background population C_LIO_LIPatients with CLL who test positive for SARS-CoV-2 in the era of the omicron variant should be considered for pre-emptive antiviral therapy C_LI Explanation of noveltyThe omicron variant has been reported to give milder disease in the general population, but outcomes of infections with the omicron variant among immunocompromised patients have not previously been reported. These population-based data on outcome for patients with CLL upon infection with the omicron variant of SARS-CoV-2 warrants closer monitoring and pre-emptive antiviral therapy upon a positive SARS-CoV-2 test for patients with CLL.