YOKOHAMA, Japan — Even as infections aboard a cruise ship contaminated by the new coronavirus continued to climb, Japan declared on Wednesday that 443 people had satisfied the terms of a two-week quarantine and let them walk free.

Much of the world seemed far from reassured.

The United States, Australia, Canada and South Korea have said that the passengers they are flying home on chartered planes will face an additional two-week quarantine, some on military bases — evidence that those countries do not believe the shipboard quarantine worked, and that more people could later test positive.

At the Yokohama port, Japanese workers also did not appear confident that those disembarking were virus-free. Drivers of the buses that ferried the passengers to airports and train stations were blocked off by plastic sheeting and tape. Workers walked around the terminal in hazmat suits. Local taxi drivers who would ordinarily meet arriving cruises said they were avoiding the ship.

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For those leaving the ship, the Diamond Princess, it was a long-awaited end to a 14-day ordeal. Over the course of five hours, the first set of passengers emerged under a bright blue sky. One of the earliest to disembark, a woman wearing a conical rice hat and a heavy-duty face mask with a strap hanging loose, was mobbed by journalists as she walked out of a guarded gate, pulling a red suitcase.

The Japanese government said that the passengers coming ashore had tested negative for the coronavirus and were safe to ride public transit and go home to their families.

But experts expressed alarm over the quarantine protocols. The number of confirmed infections on the ship reached 621 on Wednesday as 79 new cases were announced. It is the largest outbreak of the virus outside the epicenter in China.


In videos posted on YouTube, a Japanese infectious disease specialist at Kobe University said he had visited the ship on Tuesday in the hope of advising public health officials on how to prevent the further spread of infection.

The specialist, Kentaro Iwata, described the infection control measures on board as “completely chaotic.” Health ministry officials, crew members and psychiatrists would mingle and eat together, he said, while some wore full protective gear and others did not — a violation of typical procedures.

Iwata, who said he had feared contracting the coronavirus himself while on the ship, is now in a self-imposed quarantine away from his family.

The U.S. government came to a similar conclusion about the infection control measures when, in an apparent reversal of its early advice to passengers that they should stay isolated in their cabins to minimize the risk of infection, it decided to evacuate hundreds of its citizens on Monday.

In a letter to American passengers on Sunday, the U.S. Embassy in Tokyo wrote that because of mounting infections on the Diamond Princess, “the Department of Health and Human Services made an assessment that passengers and crew members on board are at high risk of exposure.”

Iwata said in an interview that Japanese health authorities had taken only “half measures” to prevent infection and “did not protect” the 3,700 passengers and crew members.


Of the people who disembarked on Wednesday, he said, “I would not be surprised if they spread infections.”

Iwata said part of the problem was that Japan’s response had been conducted by public servants who did not necessarily have expertise in infectious disease. The country does not have a government agency that specializes in disease control.

“They want to handle the case based on a successful plot that the bureaucrats created, and they just want to follow it,” he said. “Without setting an objective or goal, they just want to show they are trying hard enough, even if they end up with many infections.”

Japanese officials defended their decisions. In remarks to reporters on Wednesday, Yoshihide Suga, the chief Cabinet secretary to Prime Minister Shinzo Abe, said the country’s authorities had “made the maximum consideration to secure the health of passengers and crew.”

Gaku Hashimoto, the vice health minister, said on Twitter that upon discovering Iwata on board the ship on Tuesday, he asked him to leave. Hashimoto said the health ministry was “currently receiving help from many experts both within and outside of the ship, and is conducting an extraordinary quarantine.”

He acknowledged, though, that after three health ministry officials who had tended to passengers on the ship tested positive for the virus, “I cannot say that things are being controlled completely.”

And Katsunobu Kato, the health minister, urged those disembarking on Wednesday to limit outings to necessary trips and advised them to monitor their health conditions in the coming days.


Other infectious disease experts said they were distressed by Iwata’s description of the conditions on board.

“Hearing his account was pretty harrowing, actually,” said Benjamin Cowie, an infectious disease physician at the Peter Doherty Institute for Infection and Immunity in Melbourne, Australia.

Cowie said that after analyzing data on the new coronavirus cases reported by Japan’s health ministry since the quarantine began, he had concluded that people on the ship were contracting the virus during the period of confinement.

“Something is driving ongoing transmission on board,” he said. “There is very little doubt about that.”

Japanese health authorities said that any passenger or crew member who tested positive would be taken to a hospital, and that anyone who showed symptoms would have to remain on board until cleared by a negative test result.


More disembarkations were scheduled over the next two days. Officials said that the 443 people who left the ship on Wednesday had no symptoms and had tested negative for the virus.

It was not clear when they had taken the test, however. Some indicated that they had been tested over the weekend, which would mean they had possibly been exposed to infection for another three days.

Cowie said that people who were newly infected could test negative for the coronavirus only to become ill a few days later.

“If the government is correct and those individuals are not only clear of infection but are not incubating infection, then the decision by the authorities to release them will have proven to be the correct one,” he said. “If indeed transmission was ongoing on the ship, then ultimately I suspect that decision will be proven to be incorrect.”

One Japanese passenger chose to evacuate to South Korea with his wife, who is a South Korean citizen, because the government there is mandating a 14-day quarantine and he is concerned that he may have been infected on the ship.

The man, Yasuhito Hirasawa, a former teachers union official, said he had been tested on Saturday.


“We’re served by the kind crew members who might be possible virus carriers all the time,” Hirasawa wrote to The New York Times. “Even professional quarantine officials only wear masks and vinyl gloves, and we cannot deny the possibility of infection from the crew members, who are not experts.”

Masako Ishida, 61, who remained on board on Wednesday as she waited to receive her test results, said she was frustrated by the suggestion that anyone who tested negative should have to remain in quarantine any longer.

“I heard that some people think us passengers should be put in another two weeks in quarantine,” she said. “We were quarantined, and if we test negative, we will be given a certification that proves we’re negative. We’re one of the safest people right now.”

A mother of a customer service agent on the Diamond Princess has been exchanging text messages with her daughter, who asked to remain anonymous for fear of losing her job. In the texts, the crew member, who had watched Iwata on YouTube, said he had accurately captured the conditions on board.

The crew member said she was frightened after carrying luggage for passengers who had tested positive for the virus. The crew will be required to stay on board to help disinfect the ship after all passengers disembark. It is not clear whether they will undergo a separate quarantine period after that.

Kyle Cleveland, a sociology professor at Temple University’s Tokyo campus who has studied Japan’s response to another crisis, the Fukushima nuclear meltdowns, said he saw troubling similarities.


“It’s illustrative of a larger problem with crisis management in complex bureaucratic organizations,” Cleveland said.

“The lack of a coordinated response in which genuine experts are responsible for decision-making is problematic,” he said, “because what happens instead is that you have political functionaries who are placed in roles of authority beyond their competency. For me, the echoes and analogies with Fukushima are just really disturbing.”

Cleveland said that Japan had been handed an extremely difficult and fast-moving situation when the cruise ship arrived.

“Japan is sometimes a victim of its own competence,” he said. “Everything works and it’s a highly structured, functional society in every respect, and then when things go off the rails, they think that normal everyday processes are going to be sufficient.

“But exceptional circumstances,” he said, “require exceptional responses.”