With just days left in the current no-sail order, the Centers for Disease Control and Prevention updated a warning to defer cruise travel worldwide.

The warning was updated on Oct. 21 on the CDC website but was little noticed until Oct. 26. The current no-sail order is set to expire on Oct. 31.

The CDC first issued a Level 3 Warning on cruising on March 17, recommending against non-essential travel due to widespread ongoing transmission. (A Level 2 Alert recommends travelers “practice enhanced precautions” and a Level 1 Watch is “practice usual precautions.”) It was unclear what exactly was updated in the warning, but the Oct. 21 date suggests the CDC is reinforcing its earlier decision even as limited cruising has resumed in Europe.

“CDC recommends that travelers defer all cruise travel worldwide,” the post says. “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 several cruise ships.”

The CDC acknowledged the unusual circumstances to issue a warning about one type of transportation instead of destinations.

“CDC typically posts travel health notices for countries and other international destinations, not transportation, such as ships, airplanes, or trains. Because of the unprecedented nature of the novel coronavirus pandemic, and the increased risk of transmission of COVID-19 on cruise ships, the U.S. government is advising U.S. travelers to defer all cruise travel,” the website says.

“Recent reports of COVID-19 on cruises highlight the risk of infections to cruise passengers and crew. Like many other viruses, COVID-19 appears to spread more easily between people in close quarters aboard ships and boats. As the COVID-19 pandemic continues, there remains a risk of infected passengers and crew on board cruise ships.”

Multiple news outlets have previously reported that CDC Director Robert Redfield wanted the no-sail order extended through February 2021 but was reportedly overruled by U.S. Vice President Mike Pence.

Royal Caribbean Group and Norwegian Cruise Line Holdings together created the Healthy Sail Panel with some of the country’s leading health experts to develop guidelines to return to cruising. The panel’s recommendations were submitted to the CDC in September and included entry testing for all passengers and crew, daily temperature checks, mask recommendations and more.