Dr Ronald Lam Man-kin, controller of the Centre for Health Protection (CHP), said 860 close contacts of cluster patients had been quarantined. Also, more than 2,200 live-in household members of the close contacts had been ordered to undergo compulsory testing, involving over 100 buildings or premises.

Ursus Fitness owners speak up about ‘super-spreader’ origin

“We have also conducted DNA screening on these cluster cases and so far we haven’t found any virus variants from these cases,” he said.

Lam said many of those in the cluster failed to take adequate anti-coronavirus measures, and he called on residents not to let down their guard.

“Quite a lot of them have failed to take anti-infection measures during work, such as not wearing a mask during activities, not keeping a social distance with each other and gathering with a large group of people,” he said.

As fears of a fifth wave of infections gripped the city, respiratory expert Dr Leung Chi-chiu urged fitness workers to get tested immediately if they developed any symptoms.

Leung said he was concerned about how the Ursus Fitness outbreak could develop over the next two weeks, but believed it was under control for now, with people taking care to avoid unnecessary contact and paying fewer visits to gyms generally.

Last Friday, the government ordered all fitness centre staff to take a coronavirus test by the end of Sunday, and to be screened every 14 days.

“Even if you take the regular test for the first time, if there are new symptoms, you have to quickly get tested again,” Leung said, referring to gym workers.

Meanwhile, in an email to American citizens living in the city, the consulate said two staff members working at its Garden Road offices in Central had contracted the virus.

The pair, a man, 40, and woman, 41, were from the same family and lived in Mid-Levels’ Dynasty Court, which was among buildings locked down earlier. They are asymptomatic and last worked on Friday.

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In a statement issued late on Monday, the government said it had followed established procedures in regard to the two consulate cases.

“The cases have been admitted to the hospital for isolation, and all staff members and visitors who have been present at the relevant premises are required to undergo testing according to the relevant legislation,” it said in a statement.

The Food and Health Bureau issued a compulsory testing notice, requiring anyone who had been present at the consulate between March 2 and 15 to undergo Covid-19 screening.

The US consulate had been fully cooperative with the government, the statement added.

Earlier, Dr Albert Au ka-wing of the CHP said those who had close contact with the two cases would be sent to quarantine centres. He said the pair had not been to a gym during the incubation period but visited a bar in Central last Wednesday. The source of infection was still unknown, he said.

Lam said he did not have any information regarding media reports about the pair using diplomatic privileges to refuse being quarantined.

Approached for comment by the Post, the consulate declined to offer further information, citing privacy concerns.

In its email to citizens, it said: “We have closed the consulate general to perform a deep disinfection and cleaning while contact tracing is conducted.

“Since the start of the pandemic, we have abided by all Hong Kong government requirements for the arrival, testing, and quarantine of all diplomatic personnel and their family members.

“In coordination with Hong Kong authorities, the US consulate general and all of our staff have responsibly implemented all appropriate measures to help control the spread of Covid-19.”

The consulate added it was aware of concerns among US citizens regarding local testing, quarantine and hospitalisation procedures, “particularly in regard to the possible separation of children from their parents”, and that it was “actively addressing these concerns at the highest levels of the Hong Kong government”.

It also urged US citizens to comply with all instructions from the CHP. It cancelled all scheduled services for US citizens and visa applicants on Tuesday and Wednesday.

However, four members of the Democratic Alliance for the Betterment and Progress of Hong Kong (DAB) staged a protest outside the government headquarters in the afternoon, calling on the consulate to strictly abide by local antivirus measures and refrain from using diplomatic privileges to evade responsibilities.

“We demand that the US consulate strictly follow the measures stipulated by the government and refrain from using its diplomatic privileges to avoid testing or quarantine,” former DAB district councillor Chan Hok-fung said.

Part of Monday night’s lockdown covered Manifold Court on Po Fuk Lam Road, True Light Building on Third Street, High Park 99 on High Street and Wing Cheung Building on Western Street and was expected to end at 8am on Tuesday.

Nearby, Golden Phoenix Court on St Stephen’s Lane and neighbouring Hing Wah Mansion blocks A and M on Babington Path were also locked down, with that operation set to end at 7am.

Both Manifold Court and High Park 99 had one virus case recently, while three were reported at True Light Building. Two cases were last week detected at Hing Wah Mansion A and M blocks, while one was found in Golden Phoenix Court.