People shopping for Christmas presents should avoid spending more than 15 minutes in stores, an expert has said.
Professor Lucy Yardley of Sage told Times Radio on Sunday that the more time people spend indoors in close contact with others the more at risk of infection they will be.
Yardley said people going shopping should stick to the general rule of 15 minutes per shop, arguing it was “quite a generous amount of time”.
Asked how long is too long to spend in a shop, she said: "Well, the rule that is useful for contact tracing is that if you spend 15 minutes with somebody closer than two metres, then you have definitely had a potentially infectious contact with them.
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"So that's quite a generous amount of time, I am not sure that most of us would need that amount of time in a shop.
"And really the the less time that you spend in there, the safer you are. If you spend time, close enough to somebody and they happen to bring it on you or call for new, then it doesn't take 15 minutes to catch the virus."
However, she added that as long as people stick to social distancing rules and wear masks while indoors, Christmas shopping is "not the most dangerous thing."
Yardley also urged people to "take a step back" and think before visiting elderly relatives over the festive period.
"Is it really important for you to share your home for the entire period that's allowed?" she said. "Because that is very risky to older people who are particularly vulnerable to this infection.
"So I think, although we're allowed to do that, and some people will want to do that, the first question to ask yourself is, would it be better to put it off for a few months until they've been vaccinated?
"Which hopefully, they will be if they're very vulnerable, and do it more safely at that time."
It comes as the government and devolved administrations have agreed a temporary easing of coronavirus rules over Christmas, allowing three households to mix in a bubble for these five days.
Labour claimed that more than 2 million people travelled by train between Christmas and New Year in previous years, with millions more making car journeys.
The party is demanding transport secretary Grant Shapps present a "comprehensive travel plan" to Parliament on Monday covering the lifting of travel restrictions from December 23 to 27.
Shadow transport secretary Jim McMahon said: "Families will be looking forward to travelling to see one another this Christmas after a really tough year.
"However, we cannot afford to be complacent. The virus still poses a very serious risk to people's health.
"That's why ministers need to come to Parliament on Monday with a comprehensive travel plan to ensure families travelling across the country are kept safe and chaos on our roads and rail network is avoided."
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