The results during hospitalization (T0) differed statistically significantly from the results at 3 months after hospitalization (T1) in the severe COVID-19 population only for the following parameters: CD8 T lymphocytes (as % of lymphocytes, 23.5 vs. 32.5%, p = 0.011) and CD4 T lymphocytes (as % of lymphocytes, 51.3 vs. 47.7%, p = 0.017) (Figure 3). Here, CD4 is linked to COVID-19.