The CDC’s stringent new guidelines to ensure cruise lines are operating with strict health and safety protocols when sailing from US ports may require a full ship-wide quarantine if a single positive COVID-19 case is discovered.

The CDC’s Framework for Conditional Sailing Order, which replaced its previous No Sail Order that was in place for much of the year, states that all passengers and non-essential crew must be placed in quarantine in the event of a COVID-19 case being discovered.

The CDC head office in Atlanta.

RELATED: CDC issues travel advisory against US cruises after cancelling No Sail Order

RELATED: Cruise lines to limit all US cruises to under 7 days as part of CDC guidance

The Framework for Conditional Sailing instructs cruise lines to notify passengers and crew, and then immediately end the cruise, confining everyone to their cabins, while any infected individuals must be accommodated in a single occupancy cabin with private bathroom.

The framework adds that the cruise line must then “quarantine all remaining passengers and non-essential crew”. What isn’t clear is whether this will apply only to the return voyage to port, or whether it will include a quarantine period at the dock.

It isn’t clear whether the full quarantine will be extended at the dock such as that aboard Princess Cruises’ Diamond Princess.

An extended quarantine period, such as with Diamond Princess earlier in the year, is unlikely to sit well with many potential cruise passengers thinking of booking a voyage in the near future.

The CDC has developed a set of protocols for disembarking cruise ships that have reported a COVID-19 infection, but these guidelines have not yet been publicly released.

All passengers will need to take a rapid antigen test prior to disembarkation.

RELATED: Almost two dozen cruise ships in US alone have suffered Coronavirus outbreaks

RELATED: New cruise ship deliveries and refits delayed due to Coronavirus shutdowns

What has been confirmed is that disembarkation will involve noncommercial transportation, although the CDC has not indicated whether that is for all guests or just possible COVID-19 infected guests and those who have come in contact with them.

Additionally, it hasn’t been made clear whether it is the cruise line, insurance companies, or passengers, who will pay for the non-commercial transportation.

This is just one of a number of questions that remain up in the air as cruise lines in the US prepare to return to service in 2021. Other issues involve the pre-boarding COVID-19 tests, and who will pay for the transportation home of those who test positive prior to boarding.

In Europe, where TUI, AIDA, Costa and MSC have resumed cruises in a limited capacity out of Italy and Germany, the burden of flight cancellations, quarantine costs and so on have fallen on passengers when they have tested positive at the port.