Those issues assumed a full ship, like the Diamond Princess situation. But, if all of the "passengers" were patients, and you only used balcony rooms (to have

Those issues assumed a full ship, like the Diamond Princess situation. But, if all of the "passengers" were patients, and you only used balcony rooms (to have extra airflow available), and only used half of even those, would that mitigate the issue? Are there other options to temporarily retrofit the ventilation system? How much worse is a cruise ship ventilation system from an old hotel's HVAC? Which is harder to retrofit?