That may not be the reason for the low statistic. It’s possible the ship’s crew is underreporting illness. In the article quoted in the first post in this thread, it says:
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Recent federal studies show that sick employees were behind a majority of food contamination and foodborne illness outbreaks in the U.S. The CDC found that among outbreaks where a contributing factor was identified, 41% were caused by food contamination from ill or infectious employees.
“If a food worker stays on the job while sick and does not wash his or her hands carefully after using the toilet, the food worker can spread germs by touching food,” according to the CDC’s website. Norovirus is the leading cause of foodborne illness in the United States.
[…]
In the cruise line context, many waiters and food handlers, who are paid almost exclusively by tips, are often reluctant to go to the ship infirmary when they are ill. No cruise line, to our knowledge, provides paid sick leave to their crew members. Unfortunately, there’s an incentive to work while sick on a cruise ship in order to be paid.
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