As many as three cruise ships currently in ports and waters surrounding Asia are being quarantined for possible novel coronavirus (2019-nCoV) infections on board, in what some experts call an unnecessary "horror movie scenario," while others suggest the cruise ship settings will shed new light on the virus, including transmission patterns.
"It's one thing if you're in the middle of the ocean, but if you are at a port you can't use these people as guinea pigs," Amesh Adalja, MD, senior scholar at the Center for Health Security at Johns Hopkins University. Adalja has been following the news of the cruise ships closely, and warned on Twitter that forced quarantines will bring bad consequences all around.
"Let the passengers off and then quarantine them," Adalja told CIDRAP News. "This is an overreaction and it increases public fear to watch news reports of these ships."
Today there were a confirmed 61 people who have tested positive for 2019-nCoV on a Diamond Princess cruise which has been quarantined at the Japanese port of Yokohama since Monday, according to ABC news reports. Eleven of the 61 are Americans. Passengers who have tested positive are taken off the boat and moved to a hospital in the coastal prefecture of Kanagawa, according to Japan's Ministry of Health, Labor and Welfare.
Japan has mandated the quarantine until Feb 19. There are 2,666 guests and 1,045 crew members aboard the Diamond Princess.
At the World Health Organization (WHO) daily briefing today, Mike Ryan, MD head of the WHO's health emergencies program said the WHO spoke today with a technical team from Japan, regarding the cruise ship.
"Everything is being done for their basic needs, but it's still a very stressful situation for those involved," Ryan said. He said Japanese officials are looking into a way of cohorting
patients, so that they can get other people off the ship. He said that each newly diagnosed case, however, extends the quarantine by another 14 days for the passengers who remain onboard.
Ryan pointed out that there can be high levels of transmission in close-quarter settings such as cruise ships, even if the outbreak involves a disease that doesn't spread easily.
Cruise ships no stranger to infectious disease outbreaks
Marion Koopmans, DVM, PhD, a virologist at Erasmus Medical Center in the Netherlands, has conducted research on nororvirus infectivity on cruise ships, and said the environment makes for good case studies on infectious disease.
She told CIDRAP News she hoped health officials have a rigorous research protocols in place, so transmission patterns could be documented. She said quarantining passengers is a viable option, if done properly, but letting patients off for other forms of quarantine is also possible, Koopmans said. "Given what we see in terms of secondary transmission around travelers, this virus still seems stoppable with rigorous infection prevention."
At the WHO Media briefing, Maria Van Kerkhove, PhD, the WHO's technical lead for MERS-CoV (Middle East respiratory syndrome coronavirus) added that reports of disease spread on the ship draws attention to the need for additional studies in community settings in general. She said there's a need for early investigation in any country that has cases, and the WHO has posted early investigation protocols and hopes that countries will use them to answer unknowns.
For Adalja, much is already known about the transmission of 2019-nCoV.
"We know human-to-human transmission occurs," he said. "But how long will it take to realize that many mild cases are out there, which change the denominator of this virus."
Adalja said that 2019-nCoV likely circulated in China for weeks before detection, and thousands of people in and outside of China are probably infected with mild cases of the virus that have not caused them to seek medical attention. He cited the latest estimates from the WHO, which suggest more than 80% of nCoV cases are mild.
"We need to know the risk factors of severe disease," Adalja said. "We don't need to keep scaring Chinese populations."
Other ships await protocols
In addition to the Japanese cruise, there is Holland America's MS Westerdam cruise liner which left Singapore on January 16 that is currently not being allowed to port in various countries for fear of coronavirus. According to CNN, no cases have been diagnosed on that boat.
CNN also said in Hong Kong, the 3,600 people aboard the World Dream cruise liner, operated by Dream Cruises, have been under quarantine since earlier this week, after passengers from a former trip tested positive for the coronavirus. A total of 33 cruise members are being tested for the virus.
Today Royal Caribbean barred all travelers holding a Chinese, Hong Kong, or Macau passport from boarding its ships due to concerns over coronavirus, according to NBC News. The ban occurred after a Royal Caribbean cruise in New Jersey was delayed after four passengers from the prior cruise were taken to a hospital for coronavirus screening.
See also:
Feb 7 CNN story
Feb 7 ABC News report
Feb 7 NBC News report
CIDRAP News Editor Lisa Schnirring contributed to this story.
