DPP9 and infection: Besides, for DPP9 variant rsrs2277735:A>G, the percentage of heterozygous genotype AG in asymptomatic/mild infections (23.2%) was significantly lower than those observed in the moderate illness (43.3%, p = 0.012, OR = 0.396) and severe/fatal illness (43.8%, p = 0.01, OR = 0.388) (Figure 3d, Table S2).