These are the cruise ships with the best — and worst — sanitation scores so far this year

• The CDC randomly inspects cruise ships to help prevent the spread of stomach viruses.
• The agency has reported 13 Norovirus outbreaks on cruise ships this year.

There's nothing like a stomach virus to ruin your vacation, as hundreds of cruise ship passengers have unfortunately learned this year.

The CDC has reported 13 Norovirus outbreaks on cruise ships so far in 2023. The last time the industry's yearly gastrointestinal illness outbreak total was that high was back in 2016 — and it's only July.

In order for the agency to report a cruise ship outbreak, 3% or more of passengers or crew must report symptoms of gastrointestinal illness, such as vomiting and diarrhea, to the ship's medical staff. During the most recent outbreak, a 14-day cruise onboard the Viking Neptune in June, slightly over 13% of passengers (110 of 838) reported being ill with predominant symptoms of abdominal cramps, vomiting, and diarrhea, according to the CDC.

The nasty stomach bug isn't just a cruise ship problem, though. Norovirus cases have spiked across the United States this year, which some experts say is the result of ending COVID-19 restrictions.

"People often associate cruise ships with acute gastrointestinal illnesses such as norovirus, but acute gastrointestinal illness is relatively infrequent on cruise ships," the CDC explains on its website. "Health officials track illness on cruise ships. So outbreaks are found and reported more quickly on a cruise ship than on land."

In order to help prevent the spread of stomach viruses at sea, the CDC randomly inspects cruise ships and scores them on a scale of 0 to 100 through the Vessel Sanitation Program. Inspection scores of 85 and lower are considered "not satisfactory" by the agency.

The majority of vessels have received scores in the high nineties — only one cruise ship, the MSC Seaside, has failed the CDC's sanitation inspection so far this year. The vessel received an unusually low score of 67, nearly twenty points below the agency's passing grade.

An MSC Cruises spokesperson told Insider at the time that the cruise line launched an internal investigation based on the inspector's concerns and took immediate corrective actions.

"MSC Cruises rigorously adheres to health protocols, and the results of this inspection do not reflect the brand's high standards," the spokesperson added.

In the past 10 years, only three other cruise ships have received sanitation scores below 70, CDC records show. Violations can include something as small as not posting a raw eggs advisory on the omelette station or a single fly hovering in a food area. But before going on your next cruise adventure, it doesn't hurt to check out the ship's most recent sanitation rating.

These are the cruise ships with the highest and lowest sanitation scores so far this year:

The 15 cruise ships with perfect scores of 100

The 15 cruise ships with scores below a 95