(CNN) — Cruise ship operators may begin simulated voyages with volunteer passengers, according to an order from the US Centers for Disease Control and Prevention.
The guidelines are a new phase in the CDC's Framework for Conditional Sailing Order, released in October as a phased approach for preventing Covid-19 transmission aboard cruise ships and eventually resuming cruises with paying passengers.
The instructions include eligibility and requirements for conducting a trial voyage, which would help prepare for future restricted passenger voyages, and guide cruise ship inspection on those voyages.
Simulated voyages must have at least 10% of the maximum number of passengers permitted on board a ship. Passengers must all be at least 18 years old and confirm in writing that they're participating in a simulation voyage.
The CDC guidelines state the volunteer passengers must be able to furnish proof of vaccination or provide a letter from a physician that they are not in a high-risk category for Covid-19. And all volunteers must be willing to get a Covid-19 test three to five days after the voyage is over.
The CDC's new guidance also includes operational procedures for cruise ship operators to prevent the spread of Covid-19, including onboard surveillance, laboratory testing, face mask use, social distancing, passenger interactions and procedures for embarking and disembarking.
Since mid-April, the CDC and leaders from other federal agencies have been meeting with cruise line representatives to discuss and exchange information about the impact of vaccines and various other scientific developments since the original conditional sailing order was released.
Cruises in US waters came to a halt last March with a CDC No Sail Order. Some cruise companies have resumed operations in other parts of the world, including MSC Cruises and Costa Cruise Lines in Europe.
Many lines are targeting midsummer to resume cruising in US waters, provided they can meet CDC requirements.