is that I got sick A LOT when I was a little kid. Third of six children. Spent the first seven years of my life in a low-income housing development with lots and lots of children, and we all played together. Very few childhood immunizations back then so I got all the then-usual childhood diseases. I was 5 when the polio vaccine came out. I got influenza several times growing up, including the Asian flu. I don't bother with the flu vaccine and the last time I think I got flu was about 50 years ago.

Our immune system is designed to be challenged by diseases, and when we recover we generally have immunity to that disease.

but the reality is you don't have enough facts to arive at a reliable concusion.

something to assume any kind of general conclusion, it's still real. And valid.

For one thing, there's information out there that raising children with pets helps improve their immune systems. Also, overall, our immune system is designed to allow us to experience various diseases in our youth (the old childhood diseases of past eras) and then protect us from other diseases in adulthood. Typically, our immune system gets less effective as we get older. Sigh.

In my personal case, it seems as if all those illnesses I got in my youth and recovered from have really boosted my immune system. I last got flu around 1975 or so. I don't bother with a flu shot, although I might at some point change my mind about that. And I am not about to suggest anyone reading this should pass on a flu shot. I have gotten Covid shots and boosters, and unlike many I know who have done the same, I have not gotten Covid. It's possible that the fact I live alone and don't often see many other people is important here.

I learned that outside time and having the kids play in the dirt was extremely beneficial. Also, kids picking their noses and eating it (yuck!) was good, too.

I got sick for the first two years of teaching, but after that, maybe once a year. Preschools are the ultimate germ factory!

related factors (not viral) and are understood to be important.

A textbook example of how our immune systems are intended to work.

Unfortunately, as we saw during the pandemic, most internet "experts" who gained their knowledge from a few youtube videos, don't understand that there is a difference between bacteria and viruses.

Dirt, pollen, livestock, pets, etc.

Not viral infections.

What I do know is that I haven't been sick a single day since (I think) 1998. As a kid I grew up in a filthy house in a filthy neighborhood near a landfill -which we actually played in and picked through. I have no idea if any of that is relevant to my seeming immunity to Earth diseases, but it seems like a possibility to someone, again, with absolutely no expertise and little knowledge of medical issues.