Single-center study on SARS-CoV-2 infection in patients affected by CML: Vaccination status and bosutinib therapy as possible protective factors for hospitalization

Introduction: COVID-19 pandemic had a considerable impact among haematological patients. On the other hand, the effect of this disease on patients (pts) affected by Chronic Myeloid Leukemia (CML) is not clearly defined. Objectives: The primary objective of this study was to evaluate mortality-hospitalization rates and possible protective factors for hospitalization in CML pts affected by COVID. Methods: We collected data from CML patients followed at our institution whotested positive for SARS-CoV-2 infection. The following variables were assessed: demographical data, type of TKI therapy, vaccination status, presence of cardiovascular disease (CVD), period of infection, COVID-19 presenting symptoms, severity and mortality. Data were collected retrospectively and then analysed in univariate and multivariate analysis. Results: Out of a total of 325 CML pts treated at our institution, we recorded 72 SARS-CoV-2pts (22%) who tested positive with a SARS-CoV-2 PCR assay. Twenty two were infected in 2020 (30%), 16 patients in 2021 (22%) and 34 in 2022 (46%); with a hospitalization rate of 27%, 25% and 3% respectively. Of the 72 confirmed infections, 13 pts (18%; (CI) 10–28) were asymptomatic and 48 (66%; CI: 55–76) had mild symptoms. A total of 11 pts were admitted to hospital and 3 of these required ICU admission. No deaths were recorded. The probability of hospitalization was significantly reduced if patients were vaccinated (odds ratio OR 0.037 with CI: 0–0.33 p 0.002) or treated with Bosutinib (OR 0.06 with CI: 0–0.5 p 0.008). Conclusion: In the present study, no significant increase in mortality was noted among patients with CML as compared to the general population inItaly. Vaccination and treatment with bosutinib were identified as baseline characteristics that were associated with a decreased risk of hospitalitazion resulting from COVID-19 infection.