The line said it was cancelling the Caribbean itinerary on Odyssey of the Seas, which had been due to depart from Fort Lauderdale on 3 July after eight crew members received positive test results. The ship’s first cruise has now been pushed back to 31 July.

Royal Caribbean said it was also rescheduling a “simulation” cruise planned for later this month.

Michael Bayley, chief executive of Royal Caribbean, said: “All 1,400 crew onboard Odyssey of the Seas were vaccinated on 4 June and will be considered fully vaccinated on 18 June. The positive cases were identified after the vaccination was given and before they were fully effective.

“The eight crew members, six of whom are asymptomatic and two with mild symptoms, were quarantined and are being closely monitored by our medical team.

“To protect the remaining crew and prevent any further cases, we will have all crew quarantined for 14 days and continue with our routine testing.

“While disappointing, this is the right decision for the health and wellbeing of our crew and guests.”

Royal Caribbean is now in the process of notifying affected passengers and travel agents to explain their options.