CH prevalence among age groups appeared higher in COVID-19 patients compared to patients from this cohort (10%, 21%, 37%, and 44% of patients aged <60 years, 60–70 years, 70–80 years, and >80 years, respectively; Figure 3), especially due to a higher rate of TET2 mutations in COVID-19 patients. Here, C4B is linked to COVID-19.