My last sea command was The Big Stick from 2003-2005. During our deployment in 2005 about one third of the crew ended up with a stomach virus that made its way through the ship rather quickly. No one needed to be evacuated, but let’s just say the lines to the heads were long and uncomfortable. And there was an emergency order of toilet paper required.
The closeness of personnel on Navy ships, even one the size of an aircraft carrier, make it quite simple for things like that virus, and COVID-19 to spread rather quickly. I hope there are enough test kits to check the crew and I pray they were able to identify and isolate the three without over exposure to others. But like everywhere else, only time will tell.
Jails and prisons will potentially have similar issues.