It comes just as many countries in the EU were beginning to emerge from a fourth wave of infections driven by the Delta variant, which prompted a string of nations in the bloc to introduce harsh containment measures.
The UK is currently experiencing the largest outbreak of Omicron infections in Europe, with scientists warning that cases are doubling every two to three days.
As the variant continues to loom over the festive period, the Standard looks at how the rest of Europe is faring.
Austria, which has only just curbed a huge rise in cases sparked by the Delta variant, has recorded 70 Omicron infections as of December 16.
Its first confirmed case was announced on November 29, and was linked to a man who had recently travelled from South Africa.
Denmark has been one of the hardest-hit countries yet by the Omicron variant.
The Scandinavian nation has reported 383 cases through whole-genomic sequencing and a further 5,664 infections through variant-specific PCR testing.
The country’s SSI public health institute announced the first case of the Omicron variant on November 28.
France has now identified 170 positive cases of the Omicron variant, according to French health minister Oliver Veran.
It includes cases linked to both travel from South Africa and community transmission.
The country’s first known case was in Reunion, once of France’s overseas territories.
France on Thursday announced a travel ban on UK tourists in a bid to curb the spread of the Omicron variant. It will take effect from midnight on Friday.
Germany confirmed its first two cases of the Omicron variant last month, with both linked to travellers returning from South Africa.
There were 102 known cases as of December 16, according to the European Centre for Disease Prevention and Control (ECDC).
Germany had already introduced strict measures to deal with the spread of the Delta variant. Vaccination will become mandatory next year.
Norway has experienced the largest single outbreak of cases outside of South Africa – with 60 infections linked to a single “superspreader” event on December 5.
Another 19 cases were also confirmed after an office Christmas party in the capital Oslo.
As of December 16, 1,792 Omicron infections had been confirmed.
The Omicron variant was first identified in Portugal in 13 players from the Belenenses SAD football club after they returned from a trip to South Africa.
In a press release on November 29, the National Health Institute (Insa) said that "preliminary tests strongly suggest that all thirteen cases (...) are linked to the variant of concern Omicron".
There are currently 69 confirmed cases in the country as of December 16, according to the ECDC.
Spain detected its first case of the Omicron variant in a Madrid hospital on November 29.
"The microbiology department of the Gregorio Marañon Hospital in Madrid has announced the first confirmation of the Omicron variant in Spain," the public institution said on Twitter.
The infection was linked to a “traveller from South Africa”, they said.
Since, the number of cases has risen to 51 – though this remains far lower than the UK, France or Denmark.
The UK has the highest number of Omicron cases in Europe by quite a stretch.
According to data published by the UK Health Security Agency on December 16, the number of cases of the Omicron variant currently stands at 11,708.
Prof Neil Ferguson, a member of the government’s Scientific Advisory Group for Emergencies (Sage), said the disease “appears to be doubling every two to three days”.
On Thursday, the UK reported a record daily caseload of over 88,000 – the highest since the pandemic began.