On Thursday morning, a cruise ship with COVID-infected passengers on board docked in San Francisco, San Francisco Chronicle reported.

The Princess Ruby cruise ship carried a dozen individuals whose testing result turned out positive after 25 percent of the passengers on board were randomly tested, the Port of San Francisco said. There are a total of 724 passengers came ashore from the ship, it added.

In a statement, the Port of San Francisco said: “All individuals are either asymptomatic or experiencing mild symptoms. No passenger has required medical attention and no hospitalization is needed.”

According to officials, all ship passengers who have not received a COVID-19 booster shot yet must be tested before disembarking as the Bay Area and the United States recorded a spike in cases due to the omicron variant.

“This requirement is stricter than federal and state guidelines and is intended to protect the people of San Francisco,” according to port officials.

Also included among the requirements cruise operators have to follow is to inform the Centers for Disease Control and Prevention if they have passengers who are virus-positive, or have anyone who is suspected to be infected.

To monitor positive cases on board, a color-coded system is being used by the CDC.

Belonging in the “yellow” category was the Ruby Princess, which means that at least 0.10 percent of passengers, or at least one of the crew on board, is infected with the disease.

Princes Cruises spokesperson Negin Kamali said that the cruise, which ran for 10 days, operated as a “vaccinated cruise”. The spokesperson claimed that vaccination rates among the crew and guests are “approaching 100%”.

“Those guests who tested positive will either return home via their personal vehicles or be taken to hotels coordinated in advance for quarantine,” Kamali said.

The ship traveled to Mexico on Dec. 27 before arriving in San Francisco Thursday. Officials said that the cruise ship is set to leave San Francisco Thursday afternoon for another 10-day cruise to Mexico.