Quarantine on the Diamond Princess affected staff more than passengers, study

The Diamond Princess cruise was put into quarantine early in the pandemic which affected the staff more than the passengers, according to Japanese research.

Cruise ship Diamond Princess is seen anchored off the Yokohama Port, after ten people on the cruise liner have tested positive for coronavirus in Yokohama (photo credit: REUTERS)
Cruise ship Diamond Princess is seen anchored off the Yokohama Port, after ten people on the cruise liner have tested positive for coronavirus in Yokohama
(photo credit: REUTERS)

Japanese researchers who studied the mental health issues that flared up among passengers and crew of the quarantined Diamond Princess cruise ship early in the COVID-19 pandemic found that the staff was more anxious and depressed than the guests. 

The first signs of the pandemic came just two weeks before Israel’s third election when 14 Israelis among all 3,711 other passengers and crew members were quarantined for two weeks on the ship off the coast of Japan in February 2020. For Israel’s politicians, the virus gave them the excuse to try to persuade voters with news of their efforts to ‘rescue’ the Israelis from isolation, providing a distraction from the campaign and the then-prime minister’s difficulties.

The team from the University of Tsukuba reported that the most common mental health issue among the 3,711 people was anxiety, which was more often related to the quarantine situation than to COVID-19 itself. Other common symptoms included insomnia and depression.

Fortunately, around 70% of the mental health issues were resolved by one brief, in-person counseling session, although some people also required medication or ongoing support. Notably, although several passengers experienced suicidal thoughts, no severe outcomes such as suicide occurred during the quarantine period.

The passengers, including the Israelis, were horrified by the initial death toll of 2,000 in China where it all began, and very little was known about the zoonotic virus (originating in animals), how to treat it and prevent it. 

Buses believed to carry the U.S. passengers of the cruise ship Diamond Princess, where dozens of passengers were tested positive for coronavirus, leave at Daikoku Pier Cruise Terminal in Yokohama, south of Tokyo (credit: REUTERS)Buses believed to carry the U.S. passengers of the cruise ship Diamond Princess, where dozens of passengers were tested positive for coronavirus, leave at Daikoku Pier Cruise Terminal in Yokohama, south of Tokyo (credit: REUTERS)

Where the Japanese research all began

The Diamond Princess, owned by Carnival Corp, had been quarantined after arriving in Yokohama, southwest of Tokyo, on February 3rd. The quarantine was imposed after a man who disembarked at the ship’s previous stop in Hong Kong was diagnosed with the new coronavirus.

Twelve of the 15 Israeli nationals aboard the ship returned to Israel on a charter plane. They then had to remain in quarantine and undergo further testing at Sheba Medical Center at Tel Hashomer. The remaining Israelis had to remain on board longer. The Japanese study did not single out or mention the Israelis on board. 

The University of Tsukuba team, led by Prof. Hirokazu Tachikawa, has just published their findings in the International Journal of Disaster Risk Reduction under the title “Mental health needs associated with COVID-19 on the diamond princess cruise ship: A case series recorded by the disaster psychiatric assistance team.” 

The results showed that after 14 days of quarantine, 634 (17.1%) cases were diagnosed with COVID-19, and 328 (51.7%) cases were asymptomatic. As of April 24, 2020, 712 cases have been diagnosed and 14 deaths have occurred. The cumulative mortality rate reached 1.96%. Without an emergency evacuation plan, the total infection rate on the ship would have reached 88.47%. 

The research team found that the frequency of mental health issues was second only to that of COVID-19 infection during the quarantine. “One key finding was that mental health issues were more common in crew members than in passengers,” said Tachikawa. “Many of the crew members who sought assistance were involved in onboard health care and seemed exhausted and close to burnout, with relatively high rates of insomnia, depression and anger.”

Among both crew and passengers, women were more likely than men to experience psychological problems on the quarantined ship; this is similar to the higher incidence of mental health issues experienced by women in the general population, the team wrote. 

“Our findings of specific groups—in this case, women and crew members – who were more vulnerable to mental health issues on the ship are really important for disaster planning,” continued Tachikawa. “They highlight the need for targeted mental health support for vulnerable groups in quarantine situations. Our results shine a light on the importance of mental health support, ideally in the form of in-person counseling, in disaster responses. Responding to mental as well as physical health needs during any similar crises will be important for maintaining public health.”