The team of Bruno Quesnel shows the importance to follow COVID-19 patients and clonal hematopoiesis (Duployez et al. Cancers 2020). Clinico-Biological Features and Clonal Hematopoiesis in Patients with Severe COVID-19 Advanced age or preexisting comorbidities have been characterized as risk factors for 23 severe coronavirus disease 2019 (COVID-19) requiring hospitalization and intensive care. In recent 24 years, clonal hematopoiesis (CH) of indeterminate potential (CHIP) has emerged as a risk factor for 25 chronic inflammatory background and subsequent aging-associated diseases. The purpose of this 26 study was to identify biological factors (particularly leukocyte subtypes and inflammatory markers) 27 associated with a risk of clinical deterioration (i.e., orotracheal intubation [OTI]) and to determine 28 whether CH was likely to influence clinical and biological behavior in patients with severe COVID-29 19 requiring hospitalization. Here, we describe clinical and biological features including the 30 screening of CHIP mutants in a well-annotated cohort of 122 hospitalized patients with a laboratory-31 confirmed diagnosis of COVID-19 (55% requiring OTI). We showed that elevated white blood cell 32 counts, especially neutrophils and high C-reactive protein (CRP) levels at admission, were associated 33 with an increased requirement of OTI. We noticed a high prevalence of CH (25%, 38%, 56%, and 82% 34 of patients aged <60 y, 60-70 y, 70-80 y and >80 y) compared to a retrospective cohort of patients free 35 of hematological malignancy explored with the same pipelines (10%, 21%, 37% and 44%). However, 36 the existence CH did not significantly impact clinical outcome including OTI or death and did not 37 correlate with other laboratory findings.