Signs point to Omicron surge after holiday: expert

Hong Kong will see many more imported Omicron cases after the Christmas and New Year holiday, says infectious disease expert Ho Pak-leung.

Authorities yesterday confirmed that eight more imported cases carried the variant, including three from the United Kingdom, taking the city's Omicron tally to 27. Nine, or 33 percent, came from the UK.

The count will likely jump as Hong Kong also saw another eight imported cases yesterday, seven of whom carried the N501Y mutant strain present in Omicron. Full genetic sequencing was being done.

As some of the Omicron cases were detected in quarantine hotels, the government announced tightened measures, including requiring those living in adjacent and opposite rooms to Omicron patients to undergo daily tests until seven days after they have checked out.

One of the imported cases yesterday was a 54-year-old woman who left for the United States on Thursday and returned by Cathay Pacific flight CX881 on Sunday. As she had spent most of her incubation period in Hong Kong, authorities have added her residential building - Block 18A, Serenity Villa, Tai Po - to the mandatory test list.

Meanwhile, a nurse from Castle Peak Hospital's general adult psychiatry department tested preliminary positive after traveling to the UK. The nurse left on November 30 and returned on Monday and tested positive at the Hong Kong International Airport.

The nurse last worked in the ward on November 29 and last went to work the next day, when he attended a meeting with staff from other wards.

Although the center believed the chances of him being infected before leaving Hong Kong was "very low," the hospital tested 25 hospital workers who had met the nurse. All results were negative.

Separately, the Food and Health Bureau banned Qatar Airways flights from Doha until January 4, after flight QR818 from December 14 to Monday saw five passengers testing positive on arrival.

Authorities also upgraded Aruba, Colombia, Costa Rica, Georgia and Panama to group A regions from which non-Hong Kong residents cannot come here.

Speaking on radio, Ho from the University of Hong Kong said Omicron infections will surge on the northern hemisphere. The variant has already or will soon take over Delta as the most trending variant in Europe, the United States and the UK, especially after massive gatherings during the holiday season, he added.

Ho said as many Hongkonger return from overseas after the holiday, the SAR will record a significant surge in imported Omicron cases.

Authorities on Monday announced arrivals from group A+ countries will no longer be required to stay at Penny's Bay quarantine center for the first seven days of isolation. The period was shortened to four days from midnight yesterday.

Ho said the median incubation period for Omicron is two to three days, meaning at least half of the possible cases can be detected in Penny's Bay. He believed authorities shortened the stay to reserve capacity at the 1,916-unit public facility because more people are expected to be coming back from the UK, which was upgraded to group A+ from midnight yesterday.

Ho said the move will allow 70 percent more people to isolate in Penny's Bay.

"It's not an ideal way. But at the same time the government has required arrivals to go through more frequent tests - to 14 times in 26 days, which I think should be sufficient in guarding against imported cases," he said.

As of 9am yesterday, 705 people were observing quarantine at 568 units in Penny's Bay. Some 930 units are ready to be used, apart from those under maintenance or disinfection. From Christmas Eve on Friday, all arrivals must present negative Covid results from samples taken within 48 hours, instead of 72 hours, before flying to Hong Kong.

Ho said the tightened requirement will lower the chances of flight passengers testing positive on arrival, but it cannot completely shut off Omicron cases.

Separately, the mainland has reported six Omicron cases in three cities, including two latest from Changsha in Hunan province over the weekend.

Earlier last week, Guangzhou and Tianjin each reported one imported Omicron case.

Top mainland expert Zhong Nanshan has led research using big data and artificial intelligence proving three measures - including cancellation of public events, as well as closure at school and workplaces - are the most effective in containing outbreaks.

jane.cheung@singtaonewscorp.com