The quarantine's flop was underlined as Japanese authorities announced 79 more cases, bringing the total on the ship to 621. Results were still pending for some other passengers and crew among the original 3,711 people on board.
Japan's government has been questioned over its decision to keep people on the ship, which some experts have called a perfect virus incubator. The Diamond Princess has the most infections outside of China, where the illness known as COVID-19 emerged late last year.
Many foreign governments won't let passengers from the ship return unless they go through another quarantine period, so it was striking to see passengers disembark, get into taxis and disappear into Yokohama, where the ship is docked.
Japanese soldiers helped escort some passengers, including an elderly man in a wheelchair who wore a mask and held a cane. Some got on buses to be transported to train stations. Some people still in their cabins waved farewell from their balconies to those who had already been processed.
"I'm a bit concerned if I'm OK to get off the ship, but it was getting very difficult physically," a 77-year-old man from Saitama, near Tokyo, who got off with his wife, told Kyodo News. "For now, we just want to celebrate."
Health Minister Katsunobu Kato initially said Wednesday that those with negative virus tests had fulfilled the Japanese quarantine requirement and were free to walk out and go home on public transportation. He said passengers were only asked to watch their health carefully for a few days and notify health authorities if they have any symptoms or worries.
But after meeting with experts later in the day, he urged the former passengers to refrain from non-essential outings and try to stay home for about two weeks. "COVID-19 is not 100% known, and a lot of people got infected on the Diamond Princess. Taking those factors into consideration, we believe taking extra caution will contribute to preventing the risk of future infections," he said.
Some passengers said on Twitter they received health forms in the morning asking if they had symptoms such as a headache, fever or coughing. Passengers who tested negative and had no symptoms still had to get their body temperature checked before leaving.
Passengers were provided with a certificate stating their negative test results and completion of the quarantine. Still, Masao Sumida, an 84-year-old passenger from Chiba, near Tokyo, told NHK television he was worried people around him might have doubts. “I know I tested negative, but I'm afraid people may try to stay away from me," he said.
Mitsuo Kaku, a professor at Tohoku University's Laboratory of Infectious Disease, said on NHK that the risk of virus transmission by those who tested negative is low, but passengers who get off the ship should “use ample precautions” to protect themselves and people around them for about two more weeks.
About 500 passengers had left the ship by Wednesday evening, and Japanese officials were to spend the next three days disembarking about 2,000 others. The Diamond Princess was quarantined after one passenger who left the ship earlier in Hong Kong was found to have the virus.
Crew members, who couldn't be confined to their rooms because they were working, are expected to stay on the ship. The National Institute of Infectious Diseases said in a report Wednesday that the crew had not been fully isolated during the quarantine period. It said the quarantine was effective in reducing transmission among passengers, and that the increase in cases toward the end was mostly among crew or passengers in shared cabins.
“It should be noted that due to the nature of the ship, individual isolation of all those aboard was not possible,” it said. Some medical experts who assisted with the quarantine have said anti-infection measures were often sloppy on the ship. Four health workers — a quarantine official, a physician, a paramedic who took an infected passenger to a hospital and a health ministry official — became infected.
Chief Cabinet Secretary Yoshihide Suga said a more controlled health watch for the crew was starting immediately because they can be spread out and kept in isolation by using vacated passenger rooms.
Before the quarantine on the ship had ended, the United States evacuated more than 300 Americans and put them in quarantine in the U.S. for another 14 days. South Korea on Wednesday returned seven people from the cruise ship, placing the six South Koreans and one Japanese family member into quarantine.
Australia evacuated about 180 people early Thursday who will be staying for two weeks at a facility near the northern city of Darwin. And a chartered Cathay Pacific flight carrying 106 passengers arrived back in Hong Kong, which will quarantine them at a suburban government housing block.
Other foreign passengers were to be picked up by chartered flights sent from Canada and Italy. The U.S. government said Americans who remained on board instead of returning on the chartered flights would not be allowed to return for at least two weeks after they come ashore. Other governments picking up passengers have similar policies.
Yamaguchi reported from Tokyo. Associated Press writer Maria Cheng in London contributed to this report.