These are the 10 dirtiest cruise ships, according to the CDC — including an ultra-luxury vessel

• The CDC randomly inspects and scores cruise ships to prevent the spread of stomach viruses.
• Most vessels in 2024 have scored 95 out of 100. 85 or less is considered unacceptable.
• The 11 dirtiest ships this year so far scored 89 or less, including one that received 62 points.

On most exams, a "B" is considered a passing grade.

For cruise ships, scoring an 85 out of 100 on the Centers for Disease Control and Prevention's Vessel Sanitation Program review is considered a failure.

The CDC has reported 10 bacterial and viral outbreaks on cruise ships since the start of 2024. Most cases have been norovirus, as these often-packed floating hotels can quickly propagate the highly contagious bug through contaminated water, food, surfaces, and people.

If you're one of its unlucky victims, it could quickly ruin your vacation — the four predominant symptoms of norovirus, also known as the stomach flu, are vomiting, diarrhea, nausea, and stomach pain.

To mitigate these outbreaks, the CDC randomly conducts sanitary inspections on cruises without prior notice to the vessel. The public health agency then scores the ship from zero to 100, with outcomes of 85 or lower considered inadequate.

The review includes checking common spaces like kitchens, hot tubs, and children's activity centers.

Obvious issues, like vermin and improperly stored foods, will dock points. So will less apparent details, such as buffet handwashing stations with light sources less than 110 lux and the infrequency with which the swimming pool's hair and lint strainer is disinfected.

The CDC has inspected 119 cruise ships so far in 2024. The majority scored about 95, while 19 achieved perfect marks.

However, 11 vessels did not break into the 90s range, including two that failed to pass:

1. Crystal Serenity — Crystal Cruises, scored 89 (inspected February 3)
2. Carnival Elation — Carnival Cruise Line, scored 89 (inspected March 14)
3. Adventure of the Seas — Royal Caribbean International, scored 89 (inspected January 23)
4. National Geographic Sea Bird — Lindblad Expeditions, scored 88 (inspected July 25)
5. Carnival Miracle — Carnival Cruise Line, scored 88 (inspected April 21)
6. MSC Magnifica — MSC Cruises, scored 86 (inspected May 17)
7. Evrima — Ritz-Carlton Yacht Collection, scored 86 (inspected February 9)
8. Carnival Breeze — Carnival Cruise Line, scored 86 (inspected March 21)
9. Caribbean Princess — Princess Cruises, scored 86 (inspected March 20)
10. Hanseatic Inspiration — Hapag-Lloyd Cruises, scored 62 (inspected September 29)

The CDC inspected 181 cruise ships in 2023. Only one, MSC Seaside, scored below 85, but it was reinspected three months later and bumped to 92.

According to the public health agency's cruise review database, 75 ships have failed to exceed 85 since 1991. Hanseatic Inspiration is tied with Rederij Clipper Stad Amsterdam's Stad Amsterdam for the sixth-lowest score ever, although the latter most recently received 91 in 2019.

The CDC's review of Hapag-Lloyd's vessel noted violations such as a maggot-infested decomposing bird under the outdoor grill and dead insects in areas with food.

What the cruise lines have said

A spokesperson for Hapag-Lloyd told BI that the score does not reflect the company's standards. Following the inspection, the cruise line conducted an internal investigation and "intensive training sessions with external and internal trainers."

It plans to submit its corrective report to the CDC on time (the Vessel Sanitation Program manual states companies must submit their "corrective-action statements" within two weeks of receiving the CDC's final report).

A Crystal spokesperson told BI that most of Crystal Serenity's violations were "operational items" that have since been addressed and corrected "through harmonization of procedures and additional training with our crew."

Similarly, a spokesperson for MSC told BI it had implemented an "improvement plan" on MSC Magnifica according to the CDC inspector's suggestions. Many of the changes were immediate and only needed "minor" efforts. The cruise line now believes that Magnifica's score "is not a true reflection of the ship as it is today, and we would welcome any future inspection."

MSC noted that many of its ships frequently achieve above 90, including the MSC Meraviglia and MSC Seashore, which both received perfect marks in 2024.

Carnival, Royal Caribbean, Lindblad Expeditions, the Ritz-Carlton Yacht Collection, and Princess Cruises did not respond to a request for comment.