title: Hygiene hypothesis - old news.
authors.forename: John
authors.initials: J
authors.lastname: Mason
mesh_terms: D001424:Bacterial Infections / Q000276:immunology / Q000401:mortality*; D003141:Communicable Diseases / Q000276:immunology / Q000382:microbiology / Q000401:mortality; D006304:Health Status; D006801:Humans; D006920:Hygiene