Health officials have warned that winter vomiting bug is on the rise, with twice as many hospital beds closed as this time last year.
Hospitals in England have been forced to close more than 1,100 hospital beds over the last week due to norovirus.
NHS England urged people to stay at home if they get the bug - which causes vomiting and diarrhoea - to avoid passing it on.
They said adults and children should not go back to work or school until at least 48 hours after symptoms pass.
It comes after data from Public Health England (PHE) showed that the number of norovirus laboratory reports for November 11 to 24 was 28 per cent higher than the average for the same period in the previous five years.
Almost twice as many hospital beds have also been closed every day over the last week than at the same time last year as trusts try to stop the bug spreading between patients.
Latest figures show 1,122 beds closed, compared with 542 this time last year.
Professor Stephen Powis, medical director of the NHS, said: "We've already seen a number of hospitals and schools affected by norovirus, and unfortunately instances like these are likely to rise over the coming weeks.
"It's a really unpleasant illness to catch, but for the vast majority of people it will usually pass in a couple of days, and self-treating at home is the best way to help yourself and avoid putting others at risk.
"Crucially, if you're experiencing norovirus symptoms it's important that you don't return to work or school for 48 hours after they clear - and avoid visiting elderly or ill friends and relatives - to avoid spreading it to other people."
Nick Phin, national infection service deputy director at PHE, said: "Cases of norovirus are at higher levels than we would expect to see at this time of year, although this is not unprecedented.
"Practising good hygiene is one of the best ways to protect against norovirus.
"This includes thorough hand washing with soap and warm water after using the toilet and before eating or preparing food.
"We advise people not to visit GP surgeries and hospitals with symptoms.
"However, if they are concerned they should contact NHS 111 or talk to their GP by phone."
Norovirus is often called the winter vomiting bug because it is most common in winter.
It is highly contagious and people who have been infected can pass it on for some time.