Protective factors in breast milk and maternal antibodies could also explain why infants fared better than children aged between 1 and 3 years in an environment with HEV exposure: IgG antibodies cross the placenta well during the third trimester [38], and secretory IgA antibodies and other host defense factors in breast milk, such as lactoferrin, lysozyme, and macrophages and granulocytes, can be protective or mitigate infection [37,39]. Here, LYZ is linked to infection.