Indeed; when John Leal added chlorine to water in the early 1900s infant mortality was cut in half. After chlorination spread to most US cities this effect was

Indeed; when John Leal added chlorine to water in the early 1900s infant mortality was cut in half. After chlorination spread to most US cities this effect was replicated everywhere else too. Typhus outbreaks went from a sea-saw pattern to almost zero within a few years. Yes we need some exposure to germs. Vaccines are an excellent way to do that without the risk of catching the disease. Yes we shouldn't go overboard with antibiotics or stop kids from playing in the dirt. But there are plenty of health measures that are clearly beneficial despite lowering our exposure to germs.