Mystery case triggers silent transmission fear

A 42-year-old surveyor has become the city's first unknown source of Omicron infection, signifying silent transmission in the community, as government adviser Yuen Kwok-yung believes Hong Kong will likely enter a fifth wave of Covid-19.

The preliminary positive man, who has not been vaccinated, has not been to high-risk regions, the Covid-hit Moon Palace or Festival Walk, said the Centre for Health Protection's principal medical and health officer, Albert Au Ka-wing.

Hong Kong reported 39 new Covid cases yesterday, including 26 asymptomatic patients, taking the city's tally to 12,761. Authorities also confirmed 12 more cases were infected by the highly transmissible Omicron variant, taking the count to 114.

The male surveyor will likely become a confirmed case today, breaking the city's streak of 89 days without unknown-source infections since October 7 when a 48-year-old male airport worker living in Sha Tin was identified.

Au said the man lives in Block Two, Tsui Ning Garden, Tuen Mun, with his wife and daughter. Their residential building was locked down last night to test all residents by 6.30am today. He last went to work at Lee & Man Commercial Center in North Point on Friday.

He developed a fever and headache on Sunday and on Monday attended a private doctor, who asked him to take a deep-throat saliva test. The result came back preliminary positive yesterday.

Au said preliminary genetic sequencing suggests the man was infected by the Omicron variant, probably a recent infection.

He is being treated at the North Lantau Hospital Infection Control Centre, while his wife and daughter have been sent to Penny's Bay quarantine center.

Au said authorities are still tracing the man's whereabouts in the past 21 days, only noting he had brought his daughter to certain activities, as well as visited restaurants. But sources said the man went to M+ Museum in West Kowloon Cultural District on Thursday afternoon.

The man's daughter studies at Shun Tak Fraternal Association Tuen Mun Leung Lee Sau Yu Kindergarten, which yesterday issued a notice to parents that a parent of a lower grade pupil tested preliminary positive.

The school will suspend classes for three days for all pupils and staff to undergo Covid tests, as well as disinfection of the campus.

Au said the discovery of an unknown-source Omicron case is worrying. "It's possible that silent transmission chains already exist in the community," he said.

"Hopefully we can trace his whereabouts, send his close contacts to the quarantine center and add places he had been to the mandatory test list, in order to plug loopholes and identify his source of infection."

Speaking with Au after inspecting Moon Palace yesterday, top microbiologist Yuen from the University of Hong Kong believed the city will likely enter a fifth wave of outbreaks, adding he will not rule out the coronavirus might have already been spreading in the community.

He said the man lives in Tuen Mun, where many aircrew members also reside.

"Citizens who have been to Tuen Mun should heighten alertness and get tested if required," he said.

He urged people to get vaccinated as soon as possible. "Even one jab is good. Two jabs are better. Three jabs are the best," he said.

On the Moon Palace cluster, authorities have found all 207 patrons who had lunch there on December 27. The last six people from two tables were sent to Penny's Bay yesterday.

However, the cluster is expected to see a seventh patient in a 13-year-old girl. Her mother became a confirmed case on Sunday.

Yuen said the inspection yesterday found Moon Palace has done pretty well in anti-epidemic measures, but believed the cluster's patient zero, a now-sacked Cathay Pacific flight attendant who sat at a corner next to the VIP room, could have passed the coronavirus to patrons sitting in the VIP room.

Although the Cathay aircrew's table was separated from the VIP room with a partition, he said aerosol simulations found the coronavirus could pass through the gaps of the partition.

Separately, Chief Executive Carrie Lam Cheng Yuet-ngor admitted for the first time that border reopening talks with the mainland have been affected by the city's influx of Omicron imported cases and the Moon Palace cluster.

She said citizens will have to wait longer before cross-border travel between Hong Kong and the mainland can resume.

Meanwhile, some 1.17 million people in Yuzhou city, Henan province, were hit by a citywide lockdown yesterday, after health authorities detected three asymptomatic cases.

Genome sequencing expert Gilman Siu Kit-hang from the Polytechnic University called for authorities to shorten the quarantine period for arrivals to 14 days from 21.

Siu said most of the patients have been detected in the first week of arrival and staying in quarantine hotels for too long only increases cross-infection risks.

jane.cheung@singtaonewscorp.com