"The hygiene hypothesis is actually quite controversial because it's thought that our exposure to microbes isn't the only factor," says Cody Warren, a virologist and immunologist who is a postdoctoral fellow at the University of Colorado Boulder.
Cody Warren, inzobere mu bijyanye na virusi akaba n'umu immunologue akaba ari umunyeshuri w’iposita muri kaminuza ya Colorado Boulder, agira ati: "Igitekerezo cy’isuku mu byukuri ntikivugwaho rumwe kuko twibwira ko guhura na mikorobe atari byo byonyine."