FUT2 and viral infectious disease: Figure 1d showed different structures of HBGAs that serve as binding sites or attachment receptors for bacteria and viruses. Clinically, secretor infants have a higher risk of norovirus and rotavirus infections [23,24,25,26,27] and FUT2 variants could modify the infectious risk by altering HBGAs [26,27], thus supporting the roles of fucosylated receptors in host susceptibility to viral infections.