Live updates: follow the latest news on Covid-19 variant Omicron
The US Centre for Disease Control has urged all adults to get a booster shot as soon as possible amid fears the new Omicron strain of the coronavirus is more transmissible than Delta.
The financial centre banned non-residents from entering the city from four African countries and plans to expand that to travellers who have been to Australia, Canada, Israel and six European countries in the past 21 days due to fears over Omicron.
The World Health Organization (WHO) said on Monday the Omicron coronavirus variant carried a very high risk of infection surges, and countries around the world have tightened travel restrictions.
A statement by the Hong Kong government said non-residents from Angola, Ethiopia, Nigeria and Zambia would not be allowed to enter the global financial hub as of November 30. Residents can return if they are vaccinated but will have to quarantine for seven days in a government facility and another two weeks in a hotel at their own cost.
"Non-Hong Kong residents from these four places will not be allowed to enter Hong Kong," the statement said. "The most stringent quarantine requirements will also be implemented on relevant inbound travellers from these places."
Additionally, non-residents who have been to Australia, Austria, Belgium, Canada, the Czech Republic, Denmark, Germany, Israel, and Italy in the past 21 days would not be allowed to enter the city from December 2. Vaccinated residents returning from these countries will have to quarantine in a hotel for three weeks.
Authorities have detected three people with the Omicron variant through mandatory testing while in quarantine, but it has no known coronavirus cases in the general community.
The global financial hub is among the last places in the world pursuing a "zero-Covid" strategy and has some of the tightest travel restrictions. In coming months it hopes to partially reopen the border with mainland China, which also has no tolerance for coronavirus cases.
Canada Omicron cases rise
A further two cases of the Omicron coronavirus variant have been detected in Ottawa, bringing Canada's total number of cases to five, Ottawa Public Health said on Monday.
Earlier in the day, Quebec discovered its first case of the variant, health officials said.
Quebec Health Minister Christian Dube told reporters 115 travellers coming from countries affected by the new variant, primarily South Africa, were called and asked to isolate and test for Covid-19.
Quebec's first case was a recent traveller to Nigeria, public health director Horacio Arruda said, similar to the two cases reported on Sunday by Ontario province.
The arrival of the new variant ahead of the Christmas holiday season comes as Quebec faces a recent increase in cases, mostly in the unvaccinated, Mr Dube said. In the past 24 hours Quebec reported 756 cases.
Mr Dube urged travellers to rethink holiday trips and warned against large celebrations. The province limits gatherings in private homes to 10 people.
"The next few weeks will be critical," Mr Dube said.