Do you have good sources of fact for well-meaning grandmothers to that clearly indicate it is viruses that cause illness and not temperature?

One thing I’d love to hear is some advice on how to counter all the “facts” that (usually) grandmas tend to come out with, with regards to health. In particular things like “you’ll get a cold if your feet get wet”, and “you’ll be sick if you go out without a coat on” (even for, like, 30 seconds or something).

Any really good sources of fact that we could point these well-meaning grandmothers to that clearly indicate it is viruses that cause illness and not temperature? Any good ways of how to deal with conversations and “advice” in general when it comes to questions of health?