A ship is a germ factory. When there is a breakout, they distribute alcohol sanitizer dispensers (when hand-washing with soap is far superior, but more difficult to force people to do).

"Ship Plague" is a regular event. You'll hear someone coughing in the ship theatre one night, six are coughing the next night and the following day people are blowing their noses all over the ship. They are so frightened of going to the ship's doctor (where they will get oversized bills and maybe be quarantined to their cabin), and so done with wearing masks that they would rather infect others. (In fact, if they have a decent travel insurance policy, they would get reimbursed for their medical expenses within a week of filing their claim (with the proper paperwork).

As a passenger, it's now your job to avoid these idiots, wear an N95 mask, regularly wash your hands and so on when things seem spiraling out of control.

Jeff
(Who spent six months aboard a ship in 2022, where over 75% of the passengers and over 75% of the crew, were confined to their cabins for at least 10 days with COVID. We avoided the plague by masking and using common sense - not to mention an additional un-authorized COVID shot part-way into the trip)