Experts have issued an urgent warning ahead of tomorrow's festivities amid spiralling flu infections — calling for 'lockdown' style measures to protect the most vulnerable.
Speaking to MailOnline, public health specialists say those with even mild cold symptoms should consider self-isolating as they may unknowingly have the virus which can be fatal to older people.
Along with avoiding family gatherings, they have recommended mask-wearing and social distancing in a bid to avoid passing on the bug.
Professor Paul Hunter, an expert in infectious diseases from the University of East Anglia, said: 'If you are ill with flu you should stay away from other people for the first three days and preferably for the first week.
'This is especially important if they are elderly or suffer from medical conditions that make them more at risk.'
Flu symptoms include a fever, sore throat, muscle aches and a cough, however Prof Hunter warned many people simply suffer something similar to a common cold.
About a fifth of those infected with flu have no symptoms but can still pass the bug on to others, he added.
It comes latest data shows a high flu burden in the NHS with nearly 3,000 Brits in England hospitalised as of the end of last week with the virus, with over 150 of these considered to be in a critical condition.
This compares to just 700 total hospitalisations at the same time last year, with roughly four times fewer critical ill patients.
Experts also wanted worse could be on the way with some predicting a further surge in illness brought about by socialising over Christmas and New Year.
Rising pressures come despite data showing less than one in four frontline NHS staff have had the flu vaccine amid fears this year's version is less effective than hoped.
Professor Lawrence Young, virologist from the University of Warwick, also urged people with potential flu symptoms to consider lockdown-style measures.
'If you have flu-like symptoms, it’s really important to think about limiting your contact with other people particularly those who are clinically vulnerable to chest infections,' he said.
He added this was important to consider even if vulnerable people had received a flu jab as, like any vaccine, it cannot offer 100 per cent protection from serious illness.
Professor Ian Jones, a virologist at the University of Reading, also said it was best for people with potential flu to restrict their movements.
But he added if this wasn't possible then they should wear a mask in crowded areas to reduce possible transmission.
'It’s always difficult at this time of year but it is the best option, both for the sufferer and for those around them,' he said.
It comes as scores of Brits have flooded social media saying they are the 'sickest they have ever been' as flu continues to rip through the nation.
One Brit, hannahjaneodonnell, said on TikTok: 'I've been to death's door and back...me and the rest of the UK with whatever this weird cough thing is or whatever seasonal flu is going round.'
'That's where I've been for a week, just trying to survive. Solidarity with whoever had got what I've had and what everybody I know has had.'
Another poster, livhellewellx from Bath said from her bed: 'People aren't joking when they say the December flu situation is bad,'
'I've not felt so poorly in such a long time and it's not going away.'
People commenting on the post agreed: 'I've never felt so poorly. Just as I start to feel better I wake up feeling like day 3 over and over again.'
Another added: 'I'm 7 days in and can't believe how ill I feel - haven't had colds for years but this has pole axed me.'
User poppyanning, detailing her own illness said: 'Seriously what is in the UK air right now.'
Some Brits have called for those who have symptoms to stay home to avoid infecting the vulnerable. Asthma sufferer Tania Hunter said: 'I've been feeling awful, like someone has hit me with a tonne of bricks.'
She added: 'I know it's almost Christmas and stuff but if you and your family are sick don't go out.'
It comes as a fresh wave of NHS hospitals introduced mask mandates over fears of 'quad-demic'.
The Shrewsbury and Telford Hospital NHS Trust was latest to impose such measure in places like its emergency department and multiple wards, including those that treat cancer patients.
'Face masks will be provided in these areas, please ask a member of staff if you need one. If you feel you are exempt, please discuss this with a member of staff,' the Trust wrote in its announcement.
Flu is just one winter bug that is putting pressure on the health service, raising fears of what has been dubbed a 'quad-demic'.
Cases of norovirus and respiratory syncytial virus (RSV) as also circulating, as well as Covid and flu.
Despite continuing fears of rising flu cases, the latest official data shows just under one in four frontline healthcare workers in England have had the flu vaccine this year.
The Government report found overall just 24.3 per cent of staff responsible for direct patient care have been vaccinated for influenza.
Analysis of data showed vaccination rates are lower in every staff group, including NHS hospital staff, paramedics and GPs this year than in the 2023 season.
Pressures come amid fears that this year's version of the flu vaccine may also be less effective than hoped.
Experts have warned the jab may offer a third less protection than usual, based on cases in New Zealand and Australia where the season begins before ours.
The flu vaccine is changed each year based on data from countries in the southern hemisphere, like Australia and New Zealand ,who have their winter season six months before Britain.
This is because the same types of flu that struck those countries usually goes on to cause the majority of cases in the UK.
However, sometimes this forecasting is wrong. In 2017, a mismatched flu vaccine was responsible for 50,000 extra deaths in the UK, according to the Office of National Statistics.
Data suggests the flu jab used in the southern hemisphere, which the one being rolled out in the UK is based on, could be up to 30 per cent less effective than normal.
Experts consider a successful flu jab to be one that prevents people from needing hospital care for the virus in about 7 in 10 cases.
However, data from countries like Australia and New Zealand, suggests the latest jab only stopped 4 in 10 hospitalisations.
Flu, also called influenza, is responsible for about 40,000 hospitalisations and more than 10,000 deaths in the UK every year, though this can be higher in bad years.
The symptoms typically include fever, sore throat, muscle aches and a cough.
Experts have told this website that, while impossible to fully predict mixing over Christmas and the New Year will only increase the spread of viruses like flu, as well as return to offices and schools in 2025.
