When cells were treated with 1 μM of either Hb, hemin, or PpIX, after the initiation of infection by SARS-CoV-2, virus replication was inhibited 99.5 ± 0.4% by Hb, 100% by PpIX, and 29.1 ± 7.2% by hemin (Figure 5d). The gene discussed is GSTM1; the disease is infection.