Likewise, female patients with severe infection (0.3 ± 0.06) demonstrated elevated CB2 receptor levels compared to female patients with non-severe infection (0.20 ± 0.02) (P = 0.01) (Fig. 1.B).Furthermore, the expression level of MOR was evaluated in patients with different SARS-CoV-2 severity, revealing that the mRNA level of MOR was higher in patients with severe infection (0.42 ± 0.04) compared to non-severe infection (0.24 ± 0.02) (P = 0.002) (Fig. 1.C). This evidence concerns the gene OPRM1 and infection.