The changes can significantly speed up the city’s progress in confirming Covid-19 infections; it currently takes from a few days to more than a week to process nucleic acid tests with the exponential growth of cases.

Before the announcement of the new testing strategy, the CHP conceded that “a significant portion” of specimens could not be confirmed within 48 hours, with about 10,000 to 20,000 test results pending confirmation.

Government pandemic adviser Professor David Hui Shu-cheong said the policy change was a “good thing” because many people who tested positive were not reporting the results to the government, which led to an underestimation of infection numbers.

“People won’t have to worry about isolation any more,” he said, referring to residents who were stuck in limbo as they could only complete home isolation 14 days after returning a negative nucleic acid test result. “They can also have a record to get medical leave.”

But Hui acknowledged that there was a trade-off: “The benefit is you can immediately find out the result in 20 minutes, but the sensitivity of rapid antigen tests is 80 per cent, meaning you may miss two [positive results] out of 10 tests.”

Authorities also revealed they were switching to a more lenient screening method for overnight lockdowns, with nucleic acid tests being used only on the first day of the operation and rapid ones after that.

Covid test kits to be used to confirm Hong Kong cases. But how accurate are they?

Authorities were notified of 21,979 “reported infections”, covering both confirmed and preliminary-positive test results from all public and private labs, on Thursday. For the first time, the city also confirmed new Covid-19 infections in five digits, recording 10,010 such cases on Friday.

Amid the deepening crisis, health officials revealed that more than 400 children with Covid-19 were being treated in hospital, including a five -year-old girl who was in a critical condition.

“This number is more than the amount we can take in,” said Dr Lau Ka-hin, a chief manager at the Hospital Authority. “We are exploring whether to set up family wards in the North Lantau Hospital Hong Kong Infection Control Centre or the AsiaWorld-Expo and admit children there.”

Parents were currently allowed to stay in the same ward with their infected children if they also tested positive, he added

An unvaccinated nine-year-old boy who died on Thursday was believed to have suffered from Duchenne muscular dystrophy, according to Professor Lau Yu-lung, a paediatrician from the University of Hong Kong. Patients afflicted with the condition, characterised by progressive muscle degeneration and weakness, usually had weaker hearts, he noted. Medical experts have already established that Covid-19 could lead to heart inflammation.

A postmortem would be required to determine whether the boy’s death was caused by the virus, he said, adding: “We need to make it clear whether people died with or died from Covid-19.”

Another 47 patients aged between nine and 100 died in the 24 hours to midnight on Thursday, more than half of whom were care home residents. Just four of the 47 were fully inoculated, one had received a single shot and the rest were unvaccinated.

Twelve additional residents infected with the virus succumbed between Monday and Wednesday, but their deaths were only announced on Friday due to the information backlog. The death toll stood at 529, while as of Thursday night, 51 patients were critically ill and 48 in serious condition.

The number of confirmed cases since the pandemic began stands at 94,056.

The escalating fifth wave continued to seep into all aspects of society. More than 420 care homes for the elderly or disabled have now reported cases, with over 2,100 workers and residents testing positive so far. A total of 1,957 Hospital Authority staff have also been infected in the past two months.

The government was also working to ensure a regular supply of fresh meat after a manpower shortage due to the health crisis forced the closure of the Sheung Shui and Tsuen Wan slaughterhouses until further notice. Authorities were liaising with mainland China to supply workers so service could resume as soon as possible.

Authorities also extended a suspension of visits at correctional facilities to March 6, given a total of 337 detainees had tested positive for Covid-19.

The Hospital Authority again urged people to minimise their reliance on ambulances. More than 30 per cent of calls for service in recent days came from patients with light or no symptoms and the intense demand had delayed handling of 486 urgent cases, Dr Lau Ka-hin noted, warning the situation was “serious”.

“The Hospital Authority urges people with no or light symptoms to avoid accident and emergency departments,” he said. “As spaces in health care facilities are limited now, hospitalisation will not be arranged for Covid-19 patients with mild or no symptoms.”

With resources stretched to the limit, the authority is diverting some patients with other illnesses to private hospitals. About 200 people suffering from coronary artery disease will receive check-ups and treatment at five such facilities with the help of a HK$50 million (US$6.4 million) donation from the Li Ka Shing Foundation, according to Lau. Patients requiring specific cancer treatments will be the next batch to be transferred from public to private hospitals, he added.

Earlier, Dr Ho Pak-leung, an infectious diseases expert from the University of Hong Kong, warned that health authorities had identified only a third of the cases in the city. He suggested cold weather might have played a part in driving up Covid-related fatalities lately, and called on authorities to disclose all daily deaths, no matter the cause, so more data was available for comparison.

“For some elderly people, Covid-19 may not be their immediate cause of death. The fatalities could be affected by different factors, such as patients suffering from hypothermia, worsening of chronic diseases or lack of adequate care when they were treated in an outdoor area at the hospital,” he told a radio programme, referring to the tents set up to cope with the overflow of cases. “If we do not have this data [on overall mortality], it’s hard for us to decide what to focus our health care resources on.”

Ho said he suspected the deaths of several children with Covid-19 were linked to encephalopathy, a class of conditions affecting brain function and which can be caused by a number of factors, including infection. Encephalopathy usually occurred in children with underlying illnesses and was difficult to treat even if the patients were sent to hospital after developing symptoms, he noted.

Based on hospital data, Ho suggested as many as 200,000 people had contracted Covid-19 during the fifth wave, most of whom suffered only mild symptoms. He was basing his estimation on the 2 per cent of patients who tested positive while visiting hospitals for unrelated matters. About 2.5 per cent of residents who travelled to Macau had also tested positive upon arrival.

Assuming those rates were representative of the population, the number of undiagnosed cases circulating in the city would number well over 100,000, Ho said.

Separately, Irons Sze Wing-wai, a Hong Kong delegate to the nation’s top political advisory body, tested preliminary-positive while isolating in a hotel in Shenzhen under a special arrangement for Beijing loyalists heading to the capital for top annual meetings later next month. He would miss the talks, as would 11 other delegates and members who travelled with him on a shuttle bus and were identified as his close contacts, a source told the Post.

Hong Kong has 36 deputies who are members of the National People’s Congress and 202 delegates to the Chinese People’s Political Consultative Conference. But many of them decided to skip the meeting citing the pandemic. All those heading north tested negative in Hong Kong before crossing the border on Thursday.

Asked about protests staged by residents at the Penny’s Bay isolation facility who were not discharged on time, Lau said they were given a hotline to inquire about medical issues and a QR code that linked to a page where they could enter information to relay to staff.

“We note that the hotline was quite busy, so the Hospital Authority has tried to upgrade the hotline as well as increase manpower to manage in-calls,” he said.

In another development, two expert committees and an advisory panel to the chief executive made new vaccination recommendations after a meeting on Friday.

The experts also recommended that children aged five to 17 who had received the BioNTech vaccine for their first dose should take the second shot eight weeks later, down from 12 weeks.

Recommendations on third doses for children were also provided. Adolescents aged 12 to 17 who had received two doses of the Sinovac vaccine should take their third dose – either brand is acceptable – as soon as three months after the second shot.

If they received two BioNTech doses, the third shot should be injected five months from the last, while the Sinovac vaccine should be made available as an alternative based on personal preference.

Children aged below 12 should not take a third dose, the experts advised, based on overseas practice and the lack of supporting scientific evidence.

A fourth dose is recommended for immunocompromised patients aged 12 or above.

Additional reporting by Lilian Cheng and Danny Mok