In an aerial view, Explorer of the Seas (front), a Royal Caribbean cruise ship, along with other cruise ships are docked at Port Miami as the cruise line industry waits to begin operations again on May 26, 2021

Joe Raedle | Getty Images News | Getty Images

Royal Caribbean Cruises said Friday it isn’t changing its sailing plans this summer, despite the cruise operator reporting two positive Covid-19 cases aboard its Celebrity Millennium cruise ship on Thursday.

The two guests who tested positive during end-of-cruise testing were asymptomatic and were placed in isolation. On Friday, Royal Caribbean announced that all those who were in close contact with the two guests tested negative for the virus.

The discovery of the cases is an early test of whether the cruise operator’s safety protocols are effective in detecting the virus aboard the ship.

The Celebrity Millennium was one of the first cruises in North America to start sailing last week after being docked for over a year. The company’s first sailing out of a port in the U.S. will be the Celebrity Edge, which departs June 26 out of Fort Lauderdale, Florida.

The ship has a fully vaccinated crew and all guests over the age of 16 are required to show proof of vaccination and a negative Covid-19 test taken within 72 hours before sailing. There was also routine testing throughout the week-long cruise at every port.

The ship will dock at a port in St. Martins on Saturday.

The company’s stock was down less than 1% on Friday. It has risen 20% this year giving it a market cap of nearly $23 billion.

A passenger aboard the ship told that the mood aboard the ship had not changed and normal activities have continued.

The cruise industry has been among the last sectors to resume operations since the pandemic. There had been several high-profile outbreaks aboard cruise ships last year.

The Centers for Disease Control and Prevention has allowed the ships to resume sailing this year, after placing very strict safety protocols and requirements to prevent the spread of the virus.

—’s Seema Mody contributed to this report.