"There are a lot of reasons to believe that kids need to be exposed to things to keep their immunity complex, so that should they encounter something very dangerous, they have aspects of their immunity that might cross over and help protect them against those things," says Sara Sawyer, a professor of molecular, cellular and developmental biology at the University of Colorado Boulder.   
"Pali zifukwa zambiri zopangitsa kukhulupilira kuti ana amayenera kuyikidwa poyera ku zinthu kuti chitetezo chawo cha mnthupi chilimbe mu njira zosiyanasiyana, kuti akadzakumana ndi zina zoopsa, adzakhale ndi mbali ina ya chitetezo chawo cha mnthupi yomwe idzathandize kuwateteza ku zinthu zimenezi," anatero a Sara Sawyer, polofesa tinthu tosaoneka, maselo ndi zinthu zamoyo ku sukulu ya ukachenjede ya Colorado Boulder.