Oh my, getting sick on a ship is not fun!  I am lucky that so far it has not happened to me but I almost hate to say this since it may jinx me on my next cruise.

On one of my last two HAL ships, the norovirus was a big problem.  Lots of passengers got sick and it went on for days.  I didn't catch anything.  The ship did everything that it could to contain it and eventually their efforts paid off.