Soaring infections in Britain driven in part by the omicron variant of the coronavirus rattled Europe on Thursday, prompting new restrictions and fueling a familiar dread on both sides of the Atlantic about entering a new phase of the pandemic just in time for the holidays.

Much remains unknown about omicron, but officials increasingly warn that it appears more transmissible than the delta variant, which has already put pressure on hospitals worldwide. With so many questions unanswered, uncertainty reigned over how quickly and how severely to crack down on Christmas travel and year-end parties.

After the United Kingdom recorded its highest number of confirmed new COVID-19 infections since the pandemic began, France announced Thursday that it would tighten entry rules for those coming from Britain. Hours later, the country set another record, with a further 88,376 confirmed COVID-19 cases reported Thursday, almost 10,000 more than the day before.

In England, the chief medical officer urged people to limit who they see in the festive period. Pubs and restaurants said many people were heeding that advice by canceling Christmas parties, though there has been much debate about what's OK to do. In the United States, the White House insisted there was no need for a lockdown, despite signs that omicron was gaining ground there.

Globally, more than 75 countries have reported confirmed cases of the new variant. In Britain, where omicron cases are doubling every two to three days, omicron was expected to soon replace delta as the dominant strain in the country. The government has accelerated its booster program in response. Authorities in the 27-nation European Union say omicron will be the dominant variant in the bloc by mid-January.

Omicron traits

Early data suggest that omicron may be milder but better at evading vaccines, making booster shots more crucial. Experts have urged caution about drawing conclusions too early because hospitalizations lag infections and many variables can contribute to how sick people get.

Even if omicron proves milder on the whole than delta, it may disarm some of the lifesaving tools available and put immunocompromised and elderly people at particular risk. And if it's more transmissible, more infections overall raise the risk that more cases will be serious.

While experts gather the data, some governments rushed to act, while others sought to calm fears that the new variant would land countries back on square one.

Prime Minister Boris Johnson insisted Thursday that the situation in the U.K. is different from last year because of the widespread use of vaccines and the ability to test.

If people want to attend an event, "the sensible thing to do is to get a test and to make sure that you're being cautious,'' he said.

"But we're not saying that we want to cancel stuff. We're not locking stuff down, and the fastest route back to normality is to get boosted," he said.

Chris Whitty, England's chief medical officer, struck a more cautious note, advising people earlier in the week to limit their social contacts.

On Thursday, he told a parliamentary committee hearing that the government might have to review measures if vaccines prove less effective than expected against omicron.

He said that "would be a material change to how ministers viewed the risks going forward."

Among those taking the more cautious route was Queen Elizabeth II, who opted to cancel her traditional pre-Christmas family lunch.

U.S. response

In the United States, President Joe Biden's administration said tighter restrictions are not planned. Biden said the omicron variant is not spreading as fast as in Europe because of steps his administration has taken.

He warned, however, that unvaccinated Americans faced "a winter of severe illness and death."

White House Coronavirus Response Coordinator Jeff Zients said that the U.S. was "in a very different and stronger place than we were a year ago."

Still, feelings of unease persisted among some Americans.

Michael Stohl, 32, was relieved when he got the Pfizer vaccine last spring, but the spread of omicron has turned his optimism to dread.

"Even though I'm fully vaccinated right now, that doesn't seem to give me any sort of guarantee anymore," he said. "It just puts this anxiety over you because they tell you the boosters will work, but that's what they said about the original vaccines. Am I going to have to keep getting vaccinated every couple months?"

He said he booked an appointment to receive his booster shot Thursday morning.

Stohl, who works at the concierge desk at an apartment building in downtown Washington, said his family all lives in the city so he isn't traveling for Christmas.

He worries about friends and coworkers who will travel, however.

"I just remember how bad everything was last year, and it's looking like it might be that bad again," he said.

‘European solution’

People in the Netherlands, meanwhile, have been in a partial lockdown since November to curb a delta-driven surge. While infection numbers are now declining, the government this week ordered elementary schools to close for Christmas a week early amid fears of a new rise. Authorities also sped up a booster campaign as caretaker Prime Minister Mark Rutte cited Britain as an example of how swiftly the variant can spread.

EU leaders gathering in Brussels for a summit Thursday sought to balance tackling the surge of infections while keeping borders open with common policies throughout the bloc.

"Let's try to maintain the European solution," Belgian Prime Minister Alexander De Croo said. "If every country goes it alone again, we'll be even further from home."

But ahead of the meeting, European nations were already acting to rein in the spread.

Greece and Italy tightened entry requirements for travelers earlier this week, and Portugal decided to keep stricter border controls in place beyond its planned January 9 end.

France said Thursday that it will slap restrictions on travelers arriving from the U.K. — which is no longer part of the EU — putting limits on reasons for traveling and requiring 48 hours of isolation upon arrival. The new measures will take effect early Saturday.

French Prime Minister Jean Castex said the measures were being imposed "in the face of the extremely rapid spread of the omicron variant in the U.K."

The abrupt move comes after weeks of political tensions between France and Britain over fishing rights and how to deal with migration across the English Channel. The French government is desperately trying to avoid a new lockdown that would hurt the economy and cloud President Emmanuel Macron's expected reelection campaign.

Waiting outside a Paris train station, Constantin Dobrynin said that he sometimes felt governments overreacted and imposed unnecessary measures. As for omicron, it wasn't yet clear how serious it would be.

"So we should be balanced, and we shouldn't be panicked," he said.

Britain said it was not planning reciprocal measures.

Fearing a raft of canceled parties and a general drop in business at the height of the crucial and lucrative Christmas season, British restaurants and pubs demanded government help Thursday. They said concerns about the new variant have already wiped out 2 billion pounds ($2.6 billion) in sales over the past 10 days.

Across London, restaurants that would normally see bustling crowds clinking glasses and tucking into festive meals were reporting droves of cancellations and empty rooms.

"It's a complete nightmare. ... This week should be the busiest week of the year for hospitality," said Sally Abé, a chef at the Conrad Hotel in central London. "It's everywhere, everybody's canceling, but there's no support from the government." (AP)

•A general view of the interior of a converted call center, which is being used as an NHS COVID-19 vaccination center in Ramsgate, England, Dec. 16, 2021

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