MIAMI (CBSMiami/AP) – After more than a year without any guests at sea, cruise lines can now begin trial voyages with volunteer passengers.

On Wednesday, the Centers for Disease Control released new guidelines for the cruise industry to run so-called “simulated voyages.” The CDC action is a step toward resuming cruises in U.S. waters, possibly by July, for the first time since March 2020.

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Carnival Cruise Line Chief Executive Officer Arnold Donald said he’s cautiously optimistic about what’s ahead in the coming months.

“We still have some concerns about the recommendations, or in our case, that guidelines that make it difficult for us to get guests on board, but we’re optimistic. We’ll continue to work with the CDC and other agencies and the government and the administration,” he said.

According to the CDC guidelines, each practice cruise, from two to seven days, must have enough passengers to meet at least 10 percent of the ship’s capacity. Volunteers must be 18 or older and either fully vaccinated or free of medical conditions that would put them at high risk for severe COVID-19.

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The ship operator must tell passengers that they are simulating untested safety measures “and that sailing during a pandemic is an inherently risky activity,” the CDC guidelines state.

Passengers must be examined for COVID-19 symptoms before and after the trip, and at least 75 percent must be tested at the end.

Restrictions on board will include face masks and social distancing. The CDC will allow guided shore excursions — no wandering about on their own — if tour operators follow certain standards.

Ships must make at least one practice run before resuming regular cruises in U.S. waters, although operators will be able to avoid the requirement if they vouch that 98 percent of the crew and 95 percent% of passengers are vaccinated.

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