However, symptomatic patients demonstrated high expression levels of TMPRSS2 prior to SARS-CoV-2 infection, which significantly reduced in the presence of the virus (p < 0.001) (Figure 2), and in contrast to ACE2 levels, TMPRSS2 levels did not return to the levels observed prior to infection, thus demonstrating a difference between pre- and post-infection levels (p < 0.01) (Figure 2). Here, ACE2 is linked to infection.