Supposedly, you can catch covid again, so as long as there are rules about having to isolate when you are sick on a ship, that won’t change. I’m pretty sure cruise ships have all sick people isolate, not just people with covid.
When I took a cruise before covid on Holland America there were multiple signs about having cold or flu symptoms, we couldn’t serve ourselves at the buffet for the first 48 hours, and hand sanitizer was at every elevator lobby. It’s well known flus and other illnesses come to America via cruise ships and flights.
Eventually, there might be zero covid specific precautions if hospitalizations and deaths get low enough, but there will still be places that care about controlling the spread of illness like cruises.
I personally don’t know anyone who has had covid AND is vaccinated who has had covid twice. That would be interesting to find out if that is happening. Let’s say your chances of getting covid again are now extremely close to zero. Then your life will become much more normal than mine. I still am concerned about catching it even though I’m vaccinated.
Covid cases are way up. The positivity rate in my area is 18% now.