Over the past week, this decision-making process may well have been confused by apparent mixed messaging from the UK Government.
It comes as Boris Johnson’s administration is also in hot water over an apparently illicit Christmas party, which took place during the coronavirus lockdown last year.
So what is the Government advice for 2021 - and what do experts think about Christmas parties?
Here’s what you need to know.
What has the Government said about Christmas parties?
Until Omicron emerged last week and cases started rising steeply again, the UK appeared to be on course for a relatively normal Christmas.
Despite advice from medical bosses urging the Government to reintroduce stricter Covid measures in the Autumn, it appeared as if it had been vindicated in its decision to not bring in the next part of its Covid winter plan.
But with the first UK cases of Omicron and the uncertainty around how transmissible it is, whether vaccines work to stop it and whether it can be beaten back by immunity, the mood in Downing Street appeared to have changed.
At the same time, Health Secretary Sajid Javid said on Sunday (28 November) that people should plan for Christmas “as normal”.
This was reiterated by the Prime Minister on Tuesday (30 November) when restrictions came into force.
Having rejected a call from a senior health official to limit socialising in the run-up to Christmas, Boris Johnson insisted people should not cancel Christmas parties or school nativity plays.
Government confusion over Christmas emerges
This advice was cast into doubt when the chief of Governmental body UK Health Security Agency (UKHSA) - Dr Jenny Harries - said the Omicron variant could be kept at bay “if we all decrease our social contacts a little bit”.
She also advised “being careful, not socialising when we don’t particularly need to” and getting a booster jab.
Further confusion came on Wednesday (1 December) when Work and Pensions Secretary Therese Coffey told ITV programme Peston that people should avoid “snogging under the mistletoe” over the festive period.
Ms Coffey said kissing should be avoided with “people you don’t already know”.
Her comments were followed by George Freeman, a minister in the Department for Business, Energy and Industrial Strategy, revealing his Whitehall festive party will not be “big” and that his Christmas drinks with staff in his office had been switched to Zoom.
“I can tell you, the Department of Business, we won’t be having a big Christmas party this year. Nobody would expect us to,” he told Times Radio.
In the wake of this apparent confusion within his Government’s ranks, Boris Johnson said on Thursday (2 December) that “Government advice does not set any limits on numbers”.
“There is nothing in the rules to prevent anyone from having Christmas parties or gathering in that way,” Mr Johnson said.
He insisted “Christmas this year will be considerably better than Christmas last year”.
Meanwhile, Sajid Javid also said “people can snog who they wish” this Christmas after Labour suggested Christmas party smooching should not be part of the Government’s remit.
On Friday (3 December), Conservative Party chairperson Oliver Dowden said his party had no intention of cancelling its own Christmas drinks, and others should continue with their celebrations.
What have experts said?
While the Government has tied itself in knots over its Christmas party advice, the message from medical experts has been largely consistent - big Christmas parties are not a good idea.
Professor Peter Openshaw, a member of the Government’s New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said “the chances of getting infected were too high” to have a party.
Asked about the Prime Minister’s stance on Christmas plans, Prof Openshaw told BBC Question Time: “Personally, I wouldn’t feel safe going to a party at the moment, if it involves being indoors in an enclosed space where you’re close to other people, and people are not wearing masks.
“Even if they’ve been tested and vaccinated, I wouldn’t feel safe.”
Prof Openshaw was echoed by the British Medical Association (BMA), which said stricter Covid measures were needed.
Dr Penelope Toff, chair of the BMA’s public health medicine committee, told PA: “contradictory public health messages about Covid-19 are very unhelpful for everyone”.
Dr Toff said: “There should be no confusion about what to do over the festive period.
“There have been persistently high levels of Covid-19 infections in the community in recent months, and we now have a new variant circulating, which is worrying.
“Stronger measures need to be implemented without delay, to prevent even higher rates of spread of the virus in the community.
“People need to be encouraged to avoid large groups, to meet only outdoors where possible and face masks should be worn in all public indoor spaces except when people are seated to eat and drink.”
Meanwhile, Professor Robert West - a member of the Scientific Pandemic Insights Group on Behaviours (Spi-B), urged people to make “flexible” plans for the holiday period.
He told Sky News he personally would not make plans “that involve gatherings that can’t be changed”.
Minutes of a Sage meeting held on Monday (29 November) showed Government scientists recommended measures to reduce transmission, including reducing contacts.
It comes Covid-19 infections increased in all four UK nations - although though the latest rise is not linked to the arrival of the Omicron variant.
Around one in 60 people in private households in England had Covid-19 in the week to 27 November, up from one in 65 the previous week, according to estimates from the Office for National Statistics (ONS).
This current wave of infections has so far not resulted in similar numbers of people becoming seriously ill as during the earlier waves of the pandemic, thanks to the roll-out of Covid-19 vaccinations.
Wales recorded its first case of Omicron on Friday (3 December) and there have been 29 cases of the variant in Scotland and England respectively.
Meanwhile, the ramped-up rollout of Covid booster jabs will be in place by 13 December, according to NHS England.
Additional reporting by PA
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