Mystery cases rise to highest in single day

Jane Cheung

Hong Kong recorded 15 unknown-source infections yesterday - the highest in a single day - as the city's fifth wave rolled on despite the caseload dropping to 81 from triple digits over the last eight days.

The Centre for Health Protection warned people against cross-family gatherings during the Lunar New Year holiday from tomorrow.

That was after two recent clusters - with 10 patients each so far - came from two family gatherings of 12 to 13 people ahead of the festival.

Of the 81 new cases, four were imported and 77 local. Nine of the local infections contracted the Delta variant and most of the others were Omicron. Some 70 preliminary positive cases are pending confirmation.

Among the 15 unknown-source infections were housewives and children. They live across different districts, including Tuen Mun, Tin Shui Wai, Tai Po and Sha Tin.

Four of them contracted Delta - they all lived in Wong Tai Sin - and the others Omicron.

One of the patients lives in To Kwa Wan and authorities last night locked down his building at 18-20 Yin On Street and 17-19 Tsun Fat Street to test all residents. The target was to unseal the block at 7am today.

Shek Wah House in the Shek Lei Public Housing Estate at Kwai Chung was also locked down to test residents after sewage samples tested positive.

The Center for Health Protection's head of communicable diseases, Chuang Shuk-kwan, said although the daily number of fresh cases had fallen the proportion of untraceable source infections has increased and reached the highest in the fifth wave since it broke out on December 30.

"We're seeing cases in certain districts and housing estates, but we don't know how exactly they contracted the virus," she said.

"They're not typical clustering cases, which are often close contacts who were infected after meals or gatherings. That means there are outbreaks and transmission chains of both Omicron and Delta in the community."

On the Delta unknown-source cases, Chuang said the majority live in Choi Wan Estate.

Although most had been to the Choi Wan Commercial Complex, she said they had not been to the same restaurants or stores and authorities had still to track transmission chains.

Various buildings have seen residents living in the same unit on different floors infected, with experts suspecting vertical transmission through pipes or light wells, prompting the evacuation of residents.

They involved 12 people living in units 26 between the 36th and 39th floors of Yung Lai House in Yau Lai Public Housing Estate, Yau Tong; more than 30 people in units 6 and 7 between the second and eighth floors of Yam Yue House, Shek Yam East Estate in Kwai Chung; and dozens from units D and E between the 26th and 32nd floors of Block 2 in Tsing Yi's Tivoli Garden.

A cluster involving janitors has also emerged at Shatin Methodist College, with two people confirmed with infections yesterday, and several more tested preliminary positive. A dozen school employees were sent to quarantine centers as close contacts.

One of the Delta cases linked to the Choi Wan Estate visited the Cape Collinson Crematorium on January 23 and visitors that day have to undergo mandatory tests.

On Omicron-hit Kwai Chung Estate, all of the fresh cases yesterday were close contacts of previously infected residents and all were detected in quarantine centers or hospitals.

But Chuang refused to reveal the estate's exact number of cases, saying: "It's not so meaningful to focus on the figure at this point because none of them involved more units."

Authorities will also give out test kits in Sha Tin, Tai Po and Mong Kok districts to flush out silent carriers today after sewage samples test positive.

Meanwhile, Macanese authorities announced yesterday that Hongkongers entering the hub from 1am on Thursday must present a negative test result taken within 24 hours.

And from today authorities will resume quarantine-free schemes return2hk and come2hk for Xiangzhou district of Zhuhai after suspending it on January 18. That comes after outbreaks there eased.

jane.cheung@singtaonewscorp.com