On Saturday the agency lifted its warning to Level 4 ('very high') from Level 3 ('high').
CDC cautioned: 'It is especially important that people with an increased risk of severe illness avoid travel on cruise ships, including river cruises.'
The agency continued: 'Cruise passengers are at increased risk of person-to-person spread of infectious diseases, including COVID-19, and outbreaks of COVID-19 have been reported on cruise ships.'
People who decide to go on a cruise should get tested three to five days after their trip and stay home for seven days after travel, CDC said. Even if travelers test negative, they are advised to stay home for the full seven days.
And if passengers don't get tested, they are advised to stay home for 14 days after traveling.
Just last month CDC issued a framework for the phased resumption of cruise operations from the US. Passenger operations aren't allowed until numerous conditions are satisfied, and each ship is certified. The technical instructions for most of the order are still being drafted.
About 180 Level 4 countries
About 180 countries are currently on CDC's Level 4 'very high' COVID risk list, including the Bahamas, a destination that is expected to be key for the kind of short cruise itinearies that initially will be the focus when US cruising resumes.
Barbados, where SeaDream Yacht Club embarked the first Caribbean cruise since the pandemic shutdown before ultimately canceling the rest of its 2020 season, is currently rated Level 2, 'moderate' risk, with CDC's advice to 'avoid all nonessential travel' there.