i don't know but they are the source of many outbreaks..norovirus, legionaire's disease etc. just saw a study about the virus collecting in the air vents. At least one of the ships was not said to have good quarantine practices by an infectious disease doctor.

I think their best hope right now is to be used as docked dormitories for single workers or other groups who would neither party too hard or bring other contagious diseases on board. Perhaps older people? Don't know but they should be thoroughly cleaned with steam, regular disinfecction and UV robots.