FILE - In this Oct. 3, 2017, file photo, The Royal Caribbean Adventure of the Seas, arrives at Port Everglades in Fort Lauderdale, Fla. Royal Caribbean has announced that its ship Adventure of the Seas will resume port calls to St. Thomas on Nov. 10, and that the ship hopes to be in San Juan, Puerto Rico, and St. Martin by the end of November. It's one of a number of initiatives from the travel industry to remind consumers that the region is recovering from the impact of recent hurricanes. (Joe Cavaretta/South Florida Sun-Sentinel via AP, File)
CNN  — 

Six guests have tested positive for Covid-19 on Royal Caribbean’s Adventure of the Seas cruise ship, the cruise line confirmed Friday.

Four of the guests are vaccinated and two are unvaccinated minors, Royal Caribbean International said in a statement. The seven-night cruise departed from Nassau, Bahamas, on July 25.

One of the four vaccinated guests has mild symptoms, the company said, and three are asymptomatic. The four are not traveling together.

The two unvaccinated minors were in the same party and are asymptomatic, according to Royal Caribbean.

“The guests were immediately quarantined, and their immediate travel party and all close contacts were traced and all tested negative,” the cruise line’s statement said.

The infections were detected during routine testing that is required of all guests before returning home.

The six guests and their immediate travel parties will disembark in Freeport, Bahamas, on Friday. They will separately travel home “via private transportation,” Royal Caribbean said.

All travelers age 16 and older were required to be fully vaccinated and test negative for Covid-19 before boarding Adventure of the Seas, and all crew are fully vaccinated.

Children ineligible for vaccinations were required to take three tests, according to Royal Caribbean’s website: A PCR test prior to arriving in the Bahamas, a complimentary Covid-19 test on boarding day and a third complimentary test on day 5 or 6 of the cruise (required for all passengers ages two and up for re-entry into The Bahamas and applicable to home country re-entry requirements).

Vaccinated guests aboard Adventure of the Seas are not required to wear face coverings on the ship, according to Royal Caribbean guidelines posted on the cruise line’s website.

Unvaccinated guests are not required to wear masks outdoors but must wear masks in all indoor public spaces except while eating and drinking.

The positive cases come amid a flurry of discussions and revisions of masking requirements in the United States.

The highly transmissable Delta variant has prompted increased scrutiny on breakthrough Covid infections among the fully vaccinated and mounting concern over the threat posed to unvaccinated individuals.

The Delta variant’s rapid spread in the US prompted the Centers for Disease Control and Prevention this week to revise its masking guidance for vaccinated individuals. The agency now advises vaccinated people to wear masks in indoor public settings in areas of substantial or high transmission.