I am always fascinated by the changes that have happened over my lifespan.
I was probably 10 or 11 before I met my first person who had allergies--she was allergic to grass and at summer camp had to wear high socks and carry something to sit on rather than sit on the grass. Where grass accidentally touched her skin she promptly broke out in "rashes".
The standard was that you washed your hands after using the restroom and before dinner.
I played at the house of a friend one weekend while her older brother and sister were not feeling well. By Monday they were sick enough the doctor stopped by their house. They both had come down with polio so we had to stay away for a while. (This was before the Salk polio vaccine was invented.)
Because it was inevitable we would get chicken pox, measles and mumps, we were subject to deliberate exposure to 'get it over with', so played with sick kids when they were feeling good enough to want company. Maybe the germs were less virulent or maybe our immune systems were stronger, but it usually took several such play dates before we finally caught the diseases. We were kept isolated with and from conjunctivitis because it was not a 'one and done' disease.
It was not unusual in grade school for about 25% of the class to have 'perfect attendance' for the year because we just didn't get sick that easily.
I have watched the research and behaviors over the years. It tends to show that children raised in too sanitized environments have lower overall immunity, overuse of antibiotics has made them ineffective for some folks, and misuse of antibiotics has developed superbugs. I am interested that the most current treatments for peanut allergies are controlled exposure to small quantities.
I don't/won't use hand sanitizers or antibacterial dish or hand soaps. In the gym I wipe down equipment I have used with their sanitizer because it is gym policy, but I don't use the wipes for cart handles at the grocery store. My sense is that small exposures over time help keep the immune system strong and active.