This makes kids in more industrialized countries more vulnerable to developing autoimmune diseases, according to whats known as the "hygiene hypothesis."
Izvi zvinoita kuti vana vari munyika vakabudirira kudarika dzimwe vave panjodzi yekubata zvirwere zvinobva pakuti miviri yavo inenge isisagone kuzvivakira masoja anodzivirira hutrano hwavo, zvichienderana nezvinodaidzwa zvichinzi "fungidziro inoshandiswa patsvakurudzo dzezvehutsanana."