The C.D.C. drops its general pandemic warning system for cruise travel.

In a move celebrated by many cruise operators, the Centers for Disease Control and Prevention ended on Wednesday the tiered system that it has used for two years to publicly rate the pandemic risk of taking a cruise.

“While cruising will always pose some risk of Covid-19 transmission, travelers will make their own risk assessment when choosing to travel on a cruise ship, much like they do in all other travel settings,” a C.D.C. spokesman said in a statement.

Virgin Voyages, a cruise company owned by the British billionaire Richard Branson, applauded the agency’s decision.

“While we feel this was a long time coming, we recognize this move as a demonstration of all of the hard work this industry has done to ensure that we’re offering the safest way to travel,” Tom McAlpin, the chief executive of Virgin Voyages, said in a statement.

When the C.D.C. published its final rating under the old system on Tuesday, the agency rated cruise travel overall in the Level 2 orange or moderate-risk category. That meant that in the agency’s view, cruise travel was relatively safe for most travelers but should be avoided by unvaccinated travelers, who are at increased risk for severe illness.

From late December through February, when the Omicron surge was at its most severe in the United States, the agency rated cruise travel in its highest-risk category, Level 4, and warned all travelers, vaccinated or not, to avoid cruise ships.

The ratings have been closely watched over the past two years both by travelers who were impatient for a safe vacation and by ship operators who were desperate to make up the gargantuan losses they suffered in the long periods when they could not sail at all.

Cruise ships have been the sites of some of the most alarming and highly publicized coronavirus outbreaks, with infection spreading rapidly among guests and employees.

One early example was the Diamond Princess. One infected passenger boarded the ship in January 2020, and a month later there were more than 700 positive cases among the 3,711 passengers and crew members, with many falling seriously ill.

As horror stories spread about some people quarantining for weeks in small, windowless staterooms on the Diamond Princess and other afflicted ships, some of which were denied port entry, the future of the cruise industry seemed uncertain.

Then, as the first waves of the pandemic subsided and cruise operators sought to resume sailing, safety precautions like requiring proof of vaccination to board became political bones of contention, especially in Florida.

The C.D.C. said that while it was ending its industrywide rating for cruise travel, it would continue to publish a color-coded rating for conditions on some individual ships, based on the percentage of passengers who are vaccinated and the number of coronavirus cases reported on board.