Authorities were already mulling another citywide closure of pubs and bars to mitigate a potential fourth wave of Covid-19, according to a source.

Dr Chuang Shuk-kwan, of the Centre for Health Protection, warned that untraced cases had been increasing, with three among the latest infections.

“It’s a worrying situation and we are afraid that there may be a rebound,” she said.

Another three cases were linked to the China Secret bar in Tsim Sha Tsui, with the latest a 36-year old woman who visited the venue and stayed at Holly Mansion, and two other Thai women who also stayed in the same building. The number of infections tied to the establishment on Hart Avenue now stands at nine.

Previously, a 22-year-old student and a 26-year-old Thai woman who visited the bar on September 23 tested positive. That woman was among a group of 10 from the country suspected to be working illegally as hostesses at China Secret, according to authorities.

Another law enforcement source said the Thai hostesses were believed to have worked in at least two other bars in Yau Tsim Mong district.

Police helped health authorities track down the close contacts connected to the bar cluster, but it was described as having been a challenge given the businesses involved hostesses operating illegally. A 29-year-old patron has also tested preliminary positive.

Along with two imported infections from India, the latest cases pushed the city’s Covid-19 tally to 5,143, with 105 deaths.

Thai Covid-19 patient linked to Hong Kong bar suspected to be illegal hostess

Infections were also recorded in a care home, schools and pharmacies. In Kwai Chung, a 57-year-old male resident at the private disabled care facility Home of Treasure on Shek Yam Road was confirmed positive, while two other residents tested preliminary positive. About 30 residents and six staff deemed close contacts will be sent to quarantine centres.

Additional cases might emerge from the care home, Chuang said, as many residents did not properly wear masks and were in close contact with each other.

A pupil at a secondary school and a student at a tertiary institution were also among the newly confirmed cases. They were from the same family and attended Carmel Divine Grace Foundation Secondary School in Tseung Kwan O, and Baptist University.

The elder student attended classes late last month, developed symptoms on October 1 and sought medical treatment on Monday.

A university spokesman said all classrooms and venues linked to the case would be closed for disinfection, while some classes would be conducted online. Bottles to collect samples would be distributed to the patient’s classmates.

Hong Kong bar employee killed after midnight closure sparks triad brawl

Three employees at three pharmacies in Mong Kok were also confirmed as infected.

“Health authorities are considering if pubs should be closed again,” a government source said. “But a decision hasn’t been reached. Testing within the catering industry will start with bars, pubs and other high-risk eateries.”

Social-gathering rules would remain in force due to the increase in untraceable local infections over the past week, officials said on Tuesday. Pubs can only have two customers per table and must not operate after midnight.

But Leung, who advises the government on its pandemic strategy, said the increase in local infections proved that social-distancing measures were not strict enough.

“It might not be necessary to shut down all premises, but some measures should be tightened, and the government should decide through getting consensus from the public,” he said.

Leung asked whether schools should continue to carry out in-person classes or the government should order some entertainment premises to shut, which would nevertheless impact the economy. “It’s always a matter of choices,” he said.

The reproductive rate of the virus had risen this week to between 0.6 to 0.7, from 0.4 last week – meaning that every infected person could now be expected to pass it on to 0.7 people, he said.

“The figure could soon go up to one if nothing is done,” he warned, adding more testing should be carried out at care centres, including compulsory screening for staff and residents.

Chinese University Professor David Hui Shu-cheong, who advises the government on its pandemic response, said health officials should consider limiting the number of people allowed to gather in hotel rooms, after concerns were raised over people using them to host parties for as many as 20 people.

“They really need to be regulated, otherwise it is no different from a party room,” Hui said.

But he called the situation in bars more concerning, saying: “These kinds of bars are harder to regulate, but we should observe the situation for a while longer and see if there is a new cluster before deciding whether or not regulations need to be tightened, otherwise it is not fair to other bars.”

Bar operators should ensure only two patrons sat at each table, customers wore masks and good ventilation was maintained in their premises, he said.

Additional reporting by Zoe Low