Cruise ships may be barred from sailing in US waters until July, an order issued by the Centers for Disease Control and Prevention on Thursday said.

That ban could be lifted earlier if the CDC or the Department of Health and Human Services determines that cruises or COVID-19 are no longer major health risks.

The order also requires cruise lines to create plans to address and prevent the spread of COVID-19 on their ships.

COVID-19 has spread to hundreds of cruise-ship passengers and crew members while threatening the cruise industry's financial health.

Do you work in the cruise industry? Do you have an opinion on how your company or the industry as a whole has handled the coronavirus? Email this reporter at mmatousek@businessinsider.com.

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Cruise ships may not be able to sail in US-controlled waters until July, an order issued by the Centers for Disease Control and Prevention on Thursday said. The new order extends a prior one from March, which applied only to cruise lines that did not voluntarily halt operations, and expands it to cover all cruise lines.

Cruises, the agency said, accelerate the spread of COVID-19 and increase the burden on the US medical system.

The order bars new cruises until the Department of Health and Human Services no longer considers COVID-19 a public-health crisis, the CDC rescinds or changes the order, or 100 days pass after the order is published in the Federal Register. The document was not available in the Federal Register as of Friday morning.

The order also prevents cruise lines from letting passengers or crew members exit their ships at US ports without permission from the Coast Guard. There are 114 ships carrying over 93,000 crew members in or close to US ports, according to the CDC, and 6,000 passengers were still on Carnival's ships as of March 30, the cruise company said.

Cruise lines must create plans to address and prevent the spread of COVID-19 on their ships by April 16, the order said, adding that cruise lines must also find ways to reduce their reliance on US governments and hospitals.

"We value our relationship with the US authorities, and will continue to work with these important agencies in our shared commitment and priority for the health and safety of passengers and crew," said a representative for the Cruise Lines International Association, a trade group for the cruise industry.

The representative added that the association was concerned about the potential consequences of the CDC's order, saying it could result in the loss of 343,000 US jobs and $51 billion in economic activity if it were extended for a year.

"While it's easy to focus on cruising because of its high profile, the fact is cruising is neither the source or cause of the virus or its spread," the representative said. "What is different about the cruise industry is our reporting requirements. It would be a false assumption to connect a higher frequency in reporting to increased risk/frequency of infection."

A Royal Caribbean representative said the company was "aware of the CDC order" and "studying how best to respond to its provisions."

A Carnival Cruise Line representative said the company is evaluating the order's contents and "continuing our discussions with industry and government officials."

Norwegian Cruise Line did not immediately respond to a request for comment.

All CLIA cruise lines — including those owned by Carnival Corp., Royal Caribbean Cruises, and Norwegian Cruise Line Holdings — have been voluntarily shut down since March after COVID-19 spread to hundreds of passengers and crew members on ships like the Diamond Princess, the Costa Luminosa, and the Zaandam. The companies had planned to resume new cruises in May at the earliest, but the CDC's order could prevent any new cruises from sailing in US-controlled waters until July.

A steep decline in revenue has threatened the cruise industry's financial health, causing the stock prices of Carnival, Royal Caribbean, and Norwegian to plummet as they tap credit lines or issue bonds to fulfill their cash needs. Analysts told Business Insider that while the cruise industry would eventually rebound, it was difficult to predict when.

Do you work in the cruise industry? Do you have an opinion on how your company or the industry as a whole has handled the coronavirus? Email this reporter at mmatousek@businessinsider.com.