I guess I qualify as vaccinated, but I haven't had any boosters and my last shot was May 2021. I have not caught Covid, yet. It seems like everyone that I hear about catching it, including those here in this thread, have been vaccinated, many multiple times. I really don't think that the steps should be any different. If you feel sick, test. If you have Covid, report it and isolate, just as I hope you would if you have noro or influenza. Even if you test negative, you have SOMETHING, and it doesn't need to be shared. Stay in your cabin, if possible, until you are well.