Officials at the Health Protection Agency in England said there were 3,538 laboratory confirmed cases since the summer, an 83 percent increase compared with the same period last year, The Independent reported.
"Norovirus is very contagious, and very unpleasant," John Harris of the HPA told The Independent. "To help prevent spread of the disease, it's important that people who believe they are unwell with the virus maintain good hand hygiene and stay away from hospitals, schools and nursing homes, as these closed environments are particularly prone to outbreaks which can cause severe disruption."
There were 70 hospital outbreaks reported in Britain the two weeks before Christmas, an increase to the 61 outbreaks in the previous fortnight, the HPA said. Hospitals across the country have closed wards and restricted visitors to contain the spread of the virus.
Only a fraction of those infected with the stomach flu seek medical help. Health experts estimated for each laboratory confirmed case there are another 288 cases in the community, making 1.02 million, the HPA said.