The rise of the Omicron variant heralded on Friday another pandemic-tinged Christmas for billions, with Santa's arrival and longed-for family reunions overshadowed by the prospect of yet more COVID restrictions.
Festive jokes about reindeer having "herd immunity" and millions isolating "Home Alone" may be wearing thin, but the emergence of the ultra-infectious Omicron variant means the pandemic is not going away anytime soon.
For the second year, surging infections have complicated yuletide plans from Sydney to Seville.
The new coronavirus strain has also disrupted holiday travel, with the tracking website Flightaware.com reporting more than 2,300 flights had been cancelled around the world by 2015 GMT.
In Bethlehem - the Palestinian town in the Israeli-occupied West Bank that Christians believe was Jesus' birthplace - hoteliers have been disappointed.
After a near-total lockdown last year, Israel has again closed its borders.
Celebrations on Friday were subdued ahead of Christmas Eve midnight mass, which was to be reserved for just a small circle of people by invitation only.
"It is a bit surreal," American student Hudson Harder told AFP.
"There is a selfish part where it's like 'Oh I get to see this place so empty' but on the other hand you feel for the shops, all the money they are losing, it's really quite tragic."
'Little Things In Life'
In Europe, governments are reimposing misery-inducing safety measures that are draining the fun from Christmas for many.
The Netherlands is back in lockdown while Spain and Italy have made wearing masks compulsory outdoors.
And with Britain hitting a record high number of COVID-19 infections again on Friday for the third day in a row, British Prime Minister Boris Johnson suggested getting a vaccine booster shot as a Christmas gift for relatives.
France notched up record positive cases for the second day in a row and its health authorities urged people to get booster shots just three months after initial jabs, down from the current five.
Still, Christmas gatherings will be easier than a year ago in many other places around the world.
Most Australians are allowed to travel interstate over the festive break for the first time in two years, with Sydney's Catholic
Archbishop Anthony Fisher said that Christmas was "a ray of light" in dark times.
In the Vatican, Pope Francis during the traditional Christmas Eve Mass from St Peter's Basilica encouraged people to appreciate "the little things in life".
He also urged against "offending God's love, hurting him by despising the poor with our indifference".
Across the Atlantic, US First Lady Jill Biden took an unexpected guest to a children's hospital in Washington: her husband Joe, who is the first sitting president to accompany their spouse for the traditional Christmas book-reading.
The couple chatted with patients and doctors, showing one boy a photo of "Commander" - their new puppy - before settling into chairs beside a Christmas tree and reading a book inspired by the Disney movie "Frozen".
'Operation Present Drop'
Millions of Americans were on the move to see loved ones for Christmas, even as COVID infections surpass the peak of the previous wave and hospitals run out of beds.
Thousands could face a grim holiday weekend, with major carrier United cancelling 120 flights because infection numbers had affected flight crews and other operations.
But Santa was not deterred from doing his rounds.
The bearded spreader of holiday cheer had reportedly been cleared for travel in Canada's airspace after showing proof of vaccination and a pre-flight negative COVID test, Ottawa's transport minister said.
Santa's flight crew - including reindeer Rudolph, whose "nose shone red and bright (but) made sure he had no COVID-19 symptoms before taking off" - had also been given the all-clear.
The joint US-Canadian command, NORAD, on a specialised website offered the public the chance to track his sleigh as it flies around the globe.
Major General Eric Kenny, commander of the Canadian NORAD region, said Santa had distributed over two billion gifts and was above Pakistan around 1800 GMT.
"He's been at it for many hours already and will go throughout the evening as well," he said.
Australian authorities earlier said they were working round the clock to ensure "Operation Present Drop" went smoothly.
The aviation safety authority said Santa was "cleared to fly at 500 feet so he can skim the rooftops and deliver his presents quickly and quietly".