We no longer have pets, which makes me sad but it is what it is.
When we did have cats, I tried everything. Nothing worked. I was on the second year of allergy shots when I came down with several bouts of pneumonia. After that I wasn't allowed to get shots any more.
A few years prior to that, though, I tried an experiment. I had a half-face respirator, the kind with the removable big ugly pink filters that make you look like you starred in "The Fly".
https://www.protectly.co/products/3m...100-cartridges
I wore it whenever I was out of my bedroom but I never let any of the cats come in or sleep with me.
After 30 days, my allergist did a spirometry test and remarked on the dramatic improvement in my breathing. All for naught, though. I couldn't keep living that way, so I decided the cats would live out their natural lives but we wouldn't add any more to the herd.