The Centers for Disease Control and Prevention has raised its warning level for cruise ships to 4, the highest, and has issued a blunt warning: "avoid cruise travel regardless of vaccination status."
The number of ships that have been affected by an outbreak has grown in recent weeks, causing some ports to turn away ships. Dozens of people on a Royal Caribbean International ship tested positive after it set sail from Fort Lauderdale, Fla., and a Carnival Cruise Line ship returned to Miami after a small number of people tested positive.
The number of cases onboard made up a very slim minority of the total population and the majority of cases were not life threatening, according to the Cruise Lines International Association.
Royal Caribbean Group, one of the biggest cruise companies, said before the C.D.C. warned on Thursday that it had carried 1.1 million guests since it had resumed U.S. operations in June. The majority of passengers had mild or no symptoms.
Richard D. Fain, chairman and chief executive of Royal Caribbean Cruises, said that Omicron is having a big short-term impact on everyone, but many observers see this as a major step towards Covid-19 becoming endemic rather than epidemic.
The Mexican government said this week that it would allow cruise ships to dock at its ports even if passengers have tested positive for the coronaviruses, despite the increase in cruise ship cases.
Two cruise ships with Covid outbreak were refused permission to disembark at Puerto Vallarta, a popular tourist destination on Mexico's Pacific coast.
The country's policy of solidarity and Fraternity, as well as the principle of non- discrimination towards all people, is maintained. The health and tourism authorities are attentive to the needs of visitors.
The cruise industry was forced to shut down for 18 months because of the coronaviruses, which caused hundreds of passengers and workers to contract the disease. The C.D.C.'s Conditional Sailing Order is valid until January 15.
Most cruises out of the U.S. have crew members and adult passengers who are vaccine- and mask-free.
The prevention and control plan for each cruise ship is one of the safety measures the order requires.
Most cruise companies do not publicly announce the number of coronavirus cases identified during sailings, but all cruise ships must submit daily numbers to the C.D.C., which uses a color-coded system to inform the public whether the number of cases is public.
The C.D.C. is watching 88 cruise ships because of reported coronaviruses. The number of cases on each ship is not publicly disclosed by the agency.
