A man in his 20s was confirmed infected with the Omicron variant of the coronavirus Friday, the Tokyo metropolitan government said, adding he had visited a stadium near the capital to watch a soccer game, amid concern over the spread of potential untraceable cases of the highly transmissible strain.
The man, who lives in the capital and has been hospitalized since Wednesday, is an acquaintance of a woman who was found infected with the variant after returning from the United States on Dec. 8. After meeting with the woman, the man visited Todoroki Stadium in Kawasaki, Kanagawa Prefecture, on Sunday to watch an Emperor's Cup football semifinal match.
Three family members of the man and seven of his colleagues were identified as having been in close contact, according to the metropolitan government.
The metropolitan government and the Kawasaki city government are calling on around 80 other spectators who were seated around him at the stadium to undergo testing for the virus.
About 40 other people who were working in relative proximity to the man will stay at home for 14 days to monitor their health.
Around 130 additional people working on the same office floor as the man have been asked to take coronavirus tests but are not subject to any behavioral restrictions, the local government said.
Japan has seen a relatively subdued spread of the Omicron variant, with a total of 33 confirmed cases of the recently discovered strain. But concerns are growing over outbreaks of the variant in many other countries, at a time when Japan is removing restrictions in line with a fall in the number of coronavirus infections.
Tokyo Gov. Yuriko Koike said the man's case was not viewed as "community transmission" because authorities were able to trace the source of the infection.
Chief Cabinet Secretary Hirokazu Matsuno told a press conference Friday that authorities will "conduct tests on people who watched the soccer match around the man, regardless of the appearance of symptoms."
The Emperor's Cup semifinal in Kawasaki, near Tokyo, was held without a limit on the number of spectators, the first such sporting event in the country since the start of the COVID-19 pandemic. It drew 17,595 spectators to the stadium that has a capacity of about 25,000.
Attendance at large-scale events in Japan, such as professional sports games and concerts, has been capped at 5,000 spectators or 50 percent of venue capacity, whichever was larger. But if an event organizer presents enhanced anti-virus measures to a prefectural government, the spectator cap can be lifted.
Matsuno, the government's top spokesperson, said there were no reports of coronavirus infections at present among spectators who watched the semifinal match between Kawasaki Frontale and Oita Trinita at the stadium.
The man met on Dec. 8 and 9 with the woman in her 20s and she was hospitalized after testing positive for the virus on Monday when she was in self-quarantine at home. Her infection with the Omicron variant, believed to be more transmissible than previous strains, was confirmed Thursday.
The Kawasaki government has received information about ticket buyers from the organizer of the soccer match. It is also providing information to other municipalities about residents potentially affected.
In the meantime, Koike disclosed another confirmed case of the Omicron infection in the capital.
The man in his 50s, who returned from the United States, tested negative for the coronavirus at an airport last Saturday but developed COVID-19 symptoms the next day.
Also on Friday, Okinawa Gov. Denny Tamaki said a Japanese man in his 50s, who works at the U.S. Marines' Camp Hansen, had been infected with the highly mutated variant, the first Omicron case in the southern Japan prefecture.
At the U.S. base, a group infection of 99 COVID-19 cases has been reported, the prefectural government said. It was not known whether the Omicron infection was one of the cases.
