An outbreak of the winter vomiting bug could affect almost 880,000 this year, according to the latest figures released by health officals.
The number of laboratory confirmed cases of norovirus is 83 per cent higher than the same time last year, the Health Protection Agency (HPA) said.
So far this season there have been 3,046 confirmed cases of norovirus in England and Wales, but for every reported case there are likely to be a further 288 unreported sufferers, the HPA added.
Last season there were just 1,669 cases.
The bug has swept the country and has led to the closure of dozens of hospital wards. During the fortnight to 16 December, there were 61 outbreaks in hospitals in England. Holidaymakers on two cruise ships have also been affected.
Norovirus is highly contagious and can be transmitted through contact with an infected person or contaminated surfaces and objects. It is known to spread rapidly in closed environments such as hospitals, schools and nursing homes.
Symptoms include sudden vomiting, diarrhoea, or both, a temperature, headache and stomach cramps. The bug usually goes away within a few days.
John Harris, an expert in norovirus at the HPA, said: “The number of laboratory confirmed cases has risen again, following the drop in the number we reported last week.
“This is typical of the norovirus season where the number of laboratory reports fluctuates between October and April with the bulk of cases usually occurring between January and March.
“Norovirus is very contagious so we would urge anyone who thinks they may be unwell with norovirus to stay at home and stay away from hospitals and care homes.
“Most people will not need to go to see their doctor and will recover in a couple of days. It is important to take plenty of fluids to avoid dehydration.”