A coronavirus outbreak aboard a cruise ship that docked in New Orleans over the weekend has called into question the safety and health measures cruise lines implemented to resuscitate the industry after a yearlong pandemic shutdown.
At least 17 passengers and crew members were confirmed to have tested positive for the coronavirus while aboard a Norwegian Cruise Line ship, according to the Louisiana Department of Health.
Among them is a South African crew member, who remained in isolation for the duration of the trip and is suspected of contracting the omicron variant, Norwegian officials said.
The outbreak demonstrates the difficulty of keeping the virus away from cruise ships despite the implementation of strict public health protocols.
Outbreaks are going to occur in crowded spaces on a cruise ship no matter what, but testing travelers and staff minutes before departing and during any trip lasting more than three to five days would mitigate the transmission, said Michael Saag, professor of medicine and infectious diseases at the University of Alabama at Birmingham.
While saying outbreaks are never good, he cautioned that there shouldn't be an overreaction.
“Unless there’s more outbreaks, I don’t think we should create a policy to shut down the whole industry,” he said.
With their close confines and larger share of passengers who are older and more vulnerable, cruise ships were the sites of some of the first coronavirus outbreaks outside China.
Cruises were shut down under a "No Sail Order" issued by the Centers for Disease Control and Prevention in March 2020.
Sailing resumed over the summer with most major cruise lines requiring proof of vaccination or a negative Covid-19 test for all passengers and crew members.
But despite the best efforts of cruise ship operators to provide a healthier and safer environment for crews and passengers, including operating ships with high percentages of vaccinated persons, outbreaks of Covid have continued, the CDC reported.
In one instance between August and September, a cruise ship had an outbreak with 105 passengers and crew members being infected on a total of four consecutive voyages, according to the CDC.
In another instance between July and August, 58 passengers and crew members aboard a ship become infected, the CDC reported.
The agency has confirmed 1,359 cases between June 26 and Oct. 21.
“It’s a high-risk environment,” said Dr. William Schaffner, a professor of infectious diseases at the Vanderbilt University Medical Center in Nashville. “A cruise ship is an enclosed population where people are in close face-to-face contact often in very small places for prolonged periods of time.”
More than 3,200 people were aboard the Norwegian Breakaway when it departed New Orleans on Nov. 28, stopping in Belize, Honduras and Mexico along the voyage.
All passengers and staff were vaccinated, and those who tested positive for the coronavirus were asymptomatic, company officials said.
Federal health officials are investigating the outbreak.
“We will never compromise on health and safety and we will, of course, continue to take all appropriate action to ensure everyone’s well-being and to protect public health,” Norwegian Cruise Line said in a statement.
The ship has already returned to sea for another trip.
More than 3 million people worldwide have sailed since operations resumed, the Cruise Lines International Association, which represents 95 percent of cruise liners, told NBC News.
Saag recommends cruise passengers get tested for Covid minutes before boarding a ship and that they wear masks while touring off the boat.
“I think that’s a wise approach,” he said. “The epidemic is going to be with us quite a while longer, so what we’re going to do is use the knowledge we have and apply it.”
Schaffner, who described the Norwegian Cruise Line outbreak as "substantial," agreed.
“The virus rules and you’ve got to adapt to it,” he said.
The Cruise Lines International Association says measures similar to those are already in place, with periodic testing during and near the end of trips, as well as contact tracing and government reporting of positive cases.
Despite vaccination requirements, sailing at a reduced capacity and social distancing, cruise ships will never be Covid-proof as many of the passengers who test negative before departing will show symptoms days later, the association said.
“They’ve done everything they can. They’ve been very stringent and methodical in how they’re handling people getting on board and while they’re on the ship,” said John Lovell, president of Travel Leaders Group, a marketing and technology company representing more than 5,000 travel agencies. “You’re going to have breakthrough cases. But I firmly believe the protocols in place will keep Covid at bay.”