People browse Christmas decorations at a Hong Kong store. Health officials say the city's epidemic situation has entered a critical period. Photo: Vernon Yuen/NurPhoto/AFP

Hong Kong is suspending all flights carrying travelers from the United Kingdom after a mutated coronavirus was identified in London.

From Tuesday, people who have stayed in the UK for more than two hours will not be allowed to board flights for Hong Kong, Secretary for Food and Health Sophia Chan said on Monday. Hong Kong permanent residents who want to return from the UK will not be exempted.

Over the past two weeks, 80 out of the 1,255 cases recorded in Hong Kong were imported. Of these, 17 were from the UK.

People coming from the UK would have to submit samples for testing on the 19th or 20th day after their arrival while staying at home or hotels for seven more days on top of the 14-day quarantine period, she said.

The government was considering whether the 14-day quarantine should be extended to 21 days for all incoming travelers.

Shoppers walk on Regent Street in London. Travelers to Hong Kong from Britain face extended quarantine. Photo: by WIktor Szymanowicz/NurPhoto/AFP

Chan said there was no room for Hong Kong to loosen any social distancing rules, which include mandatory masks, restrictions on restaurant dine-in services and seating, and the shutdown of bars and clubhouses. She said all these rules would be extended from Thursday to January 6, 2021.

“Hong Kong’s epidemic situation has entered a very critical period,” Chan said. “We urge all people in Hong Kong to stay at home and avoid gatherings during the winter solstice, Christmas and New Year holidays.”

Chinese families usually have big feasts to celebrate the winter solstice, which falls on Monday this year. The government also urged civil servants to work from home and called for private companies to follow suit.

Gabriel Leung, head of the faculty of medicine at the University of Hong Kong and former Undersecretary for Food and Health, said the mutated Covid-19 virus, namely 501Y with deletion 69-70 in spike proteins, had emerged in the eastern England in late September and accounted for about 25% of all cases there until last month. However, Leung said the proportion surged to 60% this month, showing that the mutated virus had become dominant.

An analysis by his team showed that the mutated virus was 75% more infectious than the original one, or wild type, Leung said. This result matched the UK research, which showed that the mutated virus was 70% more infectious than the original.

Until now, no mutated virus from the UK had been identified in Hong Kong, Leung said. Currently, the instantaneous reproduction number R(t) of Covid-19 in Hong Kong was 0.81 but it could increase to 1.41 if the mutated virus was imported to the city, he said.

The instantaneous reproduction number reflects how infectious a virus is. A figure above one means that the epidemic is expanding.

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