The CEO of the world’s largest cruise company – which has temporarily shut down sailings due to the coronavirus pandemic – made the case in an interview aired Sunday that ships are not riskier than land-based activities when it comes to getting sick.

“A cruise ship is not a theater. It is not an arena,” said Carnival Corp. CEO Arnold Donald in an interview aired on the news program “Axios” on HBO. “It is more like Central Park. There’s a lot of natural social distancing, the ships are large, people are not always gathered and clumped together.”

His claim comes after public health experts and agencies – including the Centers for Disease Control and Prevention – have repeatedly explained why cruise ships are environments that can foster the spread of contagious illness.

“The infection prevention and control measures are difficult to implement in a ship environment because there are a number of factors that are very difficult to put under control,” Sylvie Briand, head of global infectious hazard preparedness at the World Health Organization, said in a February news conference. “We have seen this on many other occasions for other infections like noroviruses or other types of infections, so it’s not specific to COVID-19.”

Henry Wu, assistant professor of infectious diseases at Emory University’s school of medicine and director of the Emory Travel Well Center, told the Washington Post this month that shared facilities on ships – bathrooms and cafeterias, for example – are of concern, and infected crew members or incomplete cleaning can extend outbreaks onto later voyages.

“Cruises inherently have conditions that can promote infectious disease spread,” Wu said.

Donald made the comments to “Axios” while defending the decision to keep ships operating as long as the company did and insisting that cruise ships are not a source for coronavirus. Hundreds of passengers on at least four of the company’s ships have tested positive for the virus.

“We cooperated with every protocol that was in place as people learned more about coronavirus,” he said. “We ramped up screening on the ships, we ramped up detections, we ramped up in all aspects. And so 20/20 hindsight, could everyone have done something sooner? Perhaps, but it was an evolving learning situation.”

The interview came after an unprecedented couple of weeks for the cruise industry during which leaders pitched a coronavirus response plan to the government, global operators voluntarily shut down sailings for at least 30 days, and the Centers for Disease Control and Prevention and the U.S. State Department warned Americans to reschedule all cruises.

Donald’s statements aired the day before the CDC released a report on public health responses to the spread of coronavirus on cruise ships around the world in February and March. The two highest-profile outbreaks were on Carnival-owned Princess Cruises ships, but the report said confirmed cases of COVID-19, the disease caused by the coronavirus, “had been associated with at least 25 additional cruise ship voyages” as of March 17. Secondary cases in communities linked to passengers who returned from cruises also have been reported, the CDC said.

“Cruise ships are often settings for outbreaks of infectious diseases because of their closed environment, contact between travelers from many countries and crew transfers between ships,” the agency said in the update Monday published in the Morbidity and Mortality Weekly Report.

In another publication offering health advice to travelers, the CDC describes “a unique combination of health concerns” for cruise passengers.

“Travelers from diverse regions brought together in the often-crowded, semi-enclosed environments onboard ships can facilitate the spread of person-to-person, foodborne or waterborne diseases,” the agency says. “Outbreaks on ships can be sustained for multiple voyages by transmission among crew members who remain onboard or by persistent environmental contamination.”

Donald highlighted the availability of medical centers on ships to treat those who have symptoms and the practice of isolating people who fall ill on a cruise: “It manifests, you identify people who get sick, there’s a medical clinic on board, we isolate.”

“And so, in effect, you control the spread,” he continued. “Whereas when you’re in a restaurant or you’re in a public library, in a school, that does not happen.”

He added: “All I’m suggesting is that a cruise ship is not a riskier environment. People perceive it that way, but the reality is it’s not.”

The new CDC report out Monday, however, shows that it’s not always simple to determine who is infected and needs to be isolated. On the Diamond Princess, which had 712 passengers and crew test positive, 331 – or 46.5% – were asymptomatic when they were tested.

“A high proportion of asymptomatic infections could partially explain the high attack rate among cruise ship passengers and crew,” the study said. It notes that statistical models of the outbreak suggest nearly 18% of people who were infected never even developed symptoms.

And while the CDC says the disease is believed to spread between people who are within about six feet of each other through respiratory droplets, the agency says it might also be possible for someone to get sick by touching a surface or object that has the virus on it and then touching their own mouth, nose or possibly eyes.

The new CDC report says the virus was found on surfaces in cabins of symptomatic and asymptomatic Diamond Princess passengers as long as 17 days after the rooms were empty but before they had been disinfected.

“Although these data cannot be used to determine whether transmission occurred from contaminated surfaces, further study” of transmission via surfaces aboard cruise ships is warranted, the report said.

A spokesman for Carnival on Monday reiterated Donald’s sentiments, noting the number of ships with passengers who have tested positive for the virus was low compared to all sailings and passengers around the world – and compared to the global outbreak, which is nearing 400,000 confirmed cases.

In an email, Carnival’s chief communications officer Roger Frizzell pointed to restrictions on who could board a ship based on recent travel and other factors – including requiring a doctor’s note for anyone ages 70 or older – and temperature checks the industry agreed to conduct before cruises were paused.

Frizzell added that cruise ships have experience cleaning and sanitizing ships regularly. Because of that, he said, “The cruise ship environment is actually more sanitary than other environments” where the same level of sanitizing does not exist.

He said cruise ships also stand out because they are overseen and audited by health authorities such as the CDC and have to publicly report health issues to those bodies.

Most North American cruise companies have announced cancellations through early April or, in the case of Princess, May. Donald said in his interview that while he hoped the outbreak would not last forever, the company had to plan as if it would continue all year.

“I think cruises ultimately will be even better than what they were before,” he said. “And of course people love cruising. Even up until the day we paused, people wanted to cruise.”