A Princess Cruises ship that reported two recent coronavirus outbreaks had passengers test positive again while it docked in San Francisco last week. According to the Centers for Disease Control and Prevention website, the public health agency is investigating the Ruby Princess and placing the ship under observation.
The ship reported 37 cases on a trip that docked on April 23, the San Francisco Department of Public Health said in an email. The ship was returning from an Alaska tour, according to Seattle news station KOMO.
SFDPH said 95% of crew and passengers on ships disembarking in San Francisco must be fully vaccinated per an agreement between cruise lines and the Port of San Francisco. The trip had a 100% vaccination rate for the crew and 99% for guests.
Princess Cruises also requires that passengers show proof of vaccination and a negative coronavirus test to board. The cruise line did not immediately respond to a request for comment related to its latest outbreak.
Less than two weeks earlier, on a 15-day Hawaiian cruise that returned on April 11, SFDPH reported the ship had 143 coronavirus cases. The vaccination rate was 100% for both crew and passengers, and one person on that trip was hospitalized.
“The protocols that have been established work,” Princess Cruises said in a statement following the April 11 trip. “When cases are identified because of the testing onboard, cruise ship protocols help to maximize onboard containment with rapid response procedures designed to safeguard all other guests and crew as well as the communities that the ships visit.”
The cruise line said in late March that some passengers and crew on the ship, then returning from a 15-day trip to the Panama Canal, had tested positive for the coronavirus, as did passengers on another cruise in January. The March 27 voyage counted 73 cases, SFDPH said.
Of the 97 ships that have opted into CDC’s covid-19 program for cruise ships, 56 currently meet the threshold of reported cases for investigation.
The CDC lifted coronavirus rules for cruise lines earlier this year, changing its guidance for masking, testing, and vaccination requirements to voluntary recommendations. In February, Norwegian Cruise Line Holdings, Royal Caribbean Group, and Princess parent company Carnival Corp. told The Washington Post that they would take part in the program.
Coronavirus case numbers are on the rise again across the country, but there has not yet been a surge in hospitalizations. As of Wednesday afternoon, the United States saw a 23% increase in daily cases over the past seven days, with 91 new cases per 100,000 people in the past week.