When I wrote before about getting vaccinated, I assumed that Kaiser would notify me when I was eligible and they had the vaccine. Having revisited their site today I'm not sure that's right. I've not seen any discussion from either Kaiser or Fairfax.
I see Fairfax County Health Department has a vaccine registration app, which I've completed. A fair number of questions on health--allergies, etc. but it was easy enough to complete in a couple minutes. (I'm a vanilla case, answering "no" to most of the questions.) Notably, they didn't ask for my medical provider so they don't have an obvious way to cross check with Kaiser.