COVID-19 Outbreak In Cruise Ship Leaves 143 Passengers Sick Despite Vaccinations

More than a hundred vaccinated passengers aboard a cruise ship that docked in San Francisco, California, earlier this month tested positive for COVID-19, with a "vast majority" of them having experienced “mild or no symptoms,” according to the city’s health department.

The Ruby Princess returned to San Francisco from its Hawaii trip on April 11 with 143 passengers who tested positive for the coronavirus, the San Francisco Department of Public Health (SFDPH) was cited as saying in a report by CBS News.

The number was nearly double the 73 COVID-19 cases that were reported at the end of the Princess Cruises-owned vessel's previous San Francisco to Panama trip in late March, according to Mercury News.

Twelve passengers aboard the ship's Mexico cruise back in January also tested positive for the virus during random tests.

It was unclear how many passengers were aboard the Ruby Princess during its most recent Hawaii trip, but "it was quite clear that there was a large percentage of passengers that were sick," according to Antioch resident Ted Vomacka, who said he was among the people who tested positive on the cruise.

"It was obvious from observing all the coughing and hacking that some form of infection was going around," Vomacka added. "[U]nless you self-reported, you were free to keep going and infect other passengers."

The respective crews and passengers of the Ruby Princess' trips to Panama and Hawaii were 100% vaccinated, and "the vast majority of individuals who tested positive for COVID experienced mild or no symptoms," according to the SFDPH.

"Only one person was hospitalized, which speaks to the incredible efficacy of vaccination," the department said in a statement.

The Centers for Disease Control and Prevention (CDC) is now investigating the Ruby Princess over the COVID-19 outbreaks, along with four other Princess Cruises ships where the virus has surfaced, per CBS News.

The health agency is also investigating outbreaks on more than a dozen cruise ships each from Royal Caribbean and Norwegian Cruise Line.

In response to questions regarding the recent outbreaks on the Ruby Princess, Princess Cruises said in a statement that "the protocols that have been established worked.”

"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 company said.

The U.S. has reported a total of 80,807,564 COVID-19 cases and 988,707 virus-related deaths, according to data provided by the CDC.

The agency maintains that getting vaccinated "is the best way to slow down the spread of SARS-CoV-2, the virus that causes COVID-19."

Additionally, COVID-19 vaccines "are effective at preventing you from getting sick" and "are highly effective at preventing severe illness, hospitalizations, and death," the CDC said.