The relaxation of coronavirus restrictions over Christmas will increase infections “potentially by a large amount”, the government’s scientific advisers have warned.
The Scientific Advisory Group for Emergencies (SAGE) said the prevalence of COVID-19 “could easily double” over the festive period with “substantial mixing” of people.
The warning comes in a document called “notes on festive period”, which was written more than a week ago but published for the first time on Friday.
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“Any relaxation over (the) festive period will result in increased transmission and increased prevalence, potentially by a large amount,” the paper says.
“A parallel can be drawn, albeit on a different scale, between the return of students in autumn and people from different households mixing intensively over Christmas.”
SAGE says that “substantial mixing of people over a short period of time, especially those who do not make contact regularly during a month represents a significant risk for wide-spread transmission”.
“The prevalence could easily double during a few days of festive season,” it adds.
The experts say there could be further increases as newly-infected people “go back to their ‘routine’ networks”.
Around one in 85 people had coronavirus in England in the week up to 21 November, latest figures suggest.
Coronavirus rules will be relaxed over the festive season across the UK with people allowed to celebrate in three-household “Christmas bubbles” with their families.
Between 23 and 27 December, people will be able to meet with two other households to form one Christmas bubble – but only in a private home, a place of worship or public outdoor spaces.
In its document, SAGE says that “bubbles of households may be better than limiting contacts to a specific number”, but adds that “faithfulness to bubbles is paramount”.
The scientists advise that “families should be encouraged to gather in places where the smallest number of people have to share bedrooms, and there is a larger number of bathrooms”.
They also say that the “division of labour for cleaning bathrooms” is “potentially important”, and more vulnerable people should not be left with a house to clean.
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In an interview with Sky News earlier, cabinet minister Robert Jenrick acknowledged a relaxation of restrictions over Christmas will likely “drive some higher rate of infection”.
A three-tier system of restrictions will be introduced after England’s second national lockdown ends on Wednesday.
Some 99% of England’s population will fall under the two toughest tiers but Mr Jenrick said some parts of England could have their restrictions eased before Christmas.
It was announced on Friday that the UK’s coronavirus reproduction number – or R number – has fallen to between 0.9 and 1, as the UK recorded a further 16,022 coronavirus cases and 521 related deaths.