One thing people should pay attention to is how they wash. And I am the same. We buy a "bulk" size antibacterial liquid soap at Sam's Club and refill our small pump bottles. The same with hand sanitizer. But I usually don't do a good thorough wash. Dab of soap with a quick rinse. The key being is to do a good wash.
This might sound weird, but in my trade, I usually wash my hands before I go potty. And then do a quick dab and rinse.
If I use a public restroom I do wash thoroughly. And I never touch the door when leaving with my bare hands.
I am immune compromised and have a latent viral pneumonia. I got the flu in 2004 and developed a viral pneumonia complication. That pneumonia recurred in early in 2005. I went to three different MDs. They all told me the same thing. I will always carry this pneumonia virus. So, basically, if I get whatever the "normal" flu virus is for the current season, I have an added risk of that pneumonia rearing its ugly head.
The reason I am immune deficient is because of the Hep C I had for so long. I got the cure. The way they test for Hep C is checking for antibodies, and not the virus itself. So I will always test positive for Hep C. Every year that I try to stay healthy increases my immune system. But at the same time , as I grow older, my immune system lowers. It isn't a thing that is some sort of obsession. More like situational awareness, mindfulness, and rationality.