Several cruise lines have planned to resume voyages from the US after many months.

Last weekend, Royal Caribbean Group’s Celebrity Edge became the first vessel from a major operator to sail from a US port.

The Disney Dream had been scheduled to set sail today.

A Disney Cruise Line spokesman said routine Covid-19 testing came back with positive results for five of nearly 600 crew members.

All of the five were asymptomatic, had been vaccinated and had tested negative “several times before”, the spokesman said.

They were tested the day after the positive result, by the same lab, and found to be negative, the spokesman said.

The Centers for Disease Control and Prevention treats the results as positive, which prompted the cancellation of the test cruise, Disney said.

The company did not say when a new sailing would be scheduled.

Royal Caribbean executive Michael Bayley last week said two unvaccinated teenagers had tested positive on its Adventure of the Seas ship, adding that 92% of guests were fully vaccinated.