“We are worried because we may see hundreds or more cases as the Omicron variant is more transmissible. It poses a huge burden on the health care system,” Chuang said. “We have also seen some airborne transmission reported from some family gatherings, and we urge people to stay at home.”

The latest Covid-19 figure was close to the previous record of 164 infections recorded on January 27. According to health authorities, 121 of the new cases were local and 21 imported, with 31 listed as untraceable. The city’s overall coronavirus tally stands at 14,584 infections, with 213 related deaths.

Among the newly infected was Deputy Commissioner of Labour (Occupational Safety and Health) Jeff Leung Wing-yan, the government said. He is the first senior government official to fall ill with the coronavirus.

Amid the rising number of cases, the government announced that the work from home arrangement would be extended to all of the 170,000 civil servants aside from those serving essential and anti-pandemic services from Friday until February 11.

A number of government departments will also limit their services, including for inland revenue, labour, civil engineering and development, information services, building, drainage services, social welfare, and electrical and mechanical services, as well as the Housing Authority, Education Bureau and Hongkong Post.

Among the latest infections, two involved workers at a care home for the elderly at On Yam Estate in Kwai Chung and about 140 residents were sent into quarantine.

Two workers at a fish stall in Hung Hom Market were also among the confirmed cases, and the premises would be closed on Friday for deep cleaning and disinfection, while visitors would need to be tested.

Authorities identified possible vertical transmission involving several flats at Shui Pin Wai Estate in Yuen Long and affected residents were ordered to evacuate.

Chuang also pointed out that six cleaners in the city, including one who worked at Wong Tai Sin MTR station, were among the latest cases, which she attributed partially to more frequent testing for employees in the sector.

She also gave further details on the new home isolation arrangement for discharged Covid-19 patients. They do not need to undergo any Covid-19 test during the two-week period and they should monitor their health in their residences and return to hospital if necessary, she said.

Two other infections were tied to the Times Cafe in Ma On Shan, while another four employees at Sun Sun Restaurant in Jordan were also confirmed as carrying the virus.

Elsewhere in the city, authorities carried out lockdown operations at housing blocks in Tai Po, including at Fu Cheong Court, Kwai Cheong Court and Wing Cheong Court of Fortune Plaza, as well as at Hing Ping House of Tai Hing Estate in Tuen Mun.

Authorities have also detected traces of the virus in sewage samples at Ma Wan and Discovery Bay. The Home Affairs Department will distribute rapid test kits to those living or working in the area.

Earlier in the day, respiratory disease specialist Dr Leung Chi-chiu said the city lacked an effective way of detecting untraceable cases, calling it one of the weakest aspects of the pandemic-control strategy.

“There is no hope of controlling the virus when the city is still grappling with a growing number of infections,” he told a radio programme, while also calling on the government to improve case detection to align with its “dynamic zero-infection” policy.

“The government should hand out more fast-testing kits in the community, as the city has no scope to go for large-scale community testing regularly. And [authorities] should follow up on the confirmed cases faster once they detect the infection.”

In response to Leung’s comments, Chuang said she believed the current testing measures were still efficient and authorities would continue to identify high-risk areas through confirmed cases and sewage tests.

Hong Kong hits record untraceable cases, eases hospital rules for infected patients

Health chief Sophia Chan Siu-chee also pointed to compulsory testing that helped to identify the index patient who sparked an Omicron outbreak at a housing estate.

Dr Siddharth Sridhar, a clinical assistant professor at the University of Hong Kong’s department of microbiology, who said it was safe to assume the fifth wave was going to get worse as the number of untraceable cases continued to rise during the Lunar New Year holiday, when many people might be less likely to seek medical attention if they experienced symptoms.

“One of the main reasons for this is Omicron, which is more transmissible than previous variants,” he said. “Therefore, many of the public health tools used for curtailing transmission in the past are simply not as effective any more.”

He urged the city to stockpile coronavirus treatments so they could be administered to high-risk patients as soon as they were diagnosed to prevent severe cases.

Meanwhile, Dr Leung Pak-yin, a former Hospital Authority chief executive, suggested the government relax quarantine criteria for vaccinated close contacts, both to increase residents’ incentive to get their jabs, and to use limited isolation facilities more wisely.

He suggested the length of quarantine in government facilities could be shortened or replaced with home isolation for people whose entire households had received at least two doses of a vaccine.

Hongkongers give fewer red packets as pandemic dampens Lunar New Year celebrations

Respiratory disease expert Leung also called on the government to do a better job of incentivising the elderly to get inoculated, something many of them have stubbornly resisted.

“Far water can’t put out near fire,” he said, warning the elderly to get vaccinated now rather than wait for the city to achieve “out-of-reach” community immunity.

The percentage of Hongkongers aged 80 and up who had received at least one dose of a vaccine was just 31.3 per cent as of Thursday, less than half the rate for the overall eligible population. For those aged 70 to 79, it was 59.6 per cent.

Leung suggested the government waive a month’s elderly care home fees or offer an extra month’s old age allowance for elderly people to take their shots.

Meanwhile, Hospital Authority chief manager Dr Lau Ka-hin said a 77-year-old elderly woman infected with the Delta variant remained in critical condition. The woman, who is unvaccinated, is the first critical case of the fifth wave. She suffers from chronic diseases such as diabetes and hyperlipidemia.

Lau also warned that demand for isolation beds could surge as the pandemic becomes more severe and he urged the elderly and chronically ill to get vaccinated to help reduce the strain on health services.