Health officials in the United Kingdom have warned about a sharp increase in confirmed cases of norovirus.

National surveillance data shows laboratory reports of the virus in England are 66 percent higher than the average at this time of year, according to the UK Health Security Agency (UKHSA).

Total lab reports during weeks 3 and 4 of the 2022-2023 norovirus season were 527 which is up from the 5-season average of 318 reports for the same two-week period.

The biggest rise in lab-confirmed norovirus is in people aged 65 and older. Such high levels in this age group haven’t been seen in over a decade, said the UKHSA.

Outbreaks caused by norovirus have increased in hospitals, schools, and care homes, with the majority reported in care home settings. Up to week 4 of the 2022-2023 season, 78 outbreaks in hospitals were lab confirmed as norovirus.

How to reduce the risk of getting sick
UKHSA is reminding people of actions they can take to reduce the risk of norovirus. The virus is highly infectious and is easily spread through contact with someone with the infection or contaminated surfaces. One of the best ways to prevent the spread is through good hand hygiene.

If ill, avoid cooking and preparing meals for others until 48 hours after symptoms have stopped, as norovirus can be spread through food contaminated by the virus when it is handled by symptomatic people or infected individuals.

“Please stay at home if you are experiencing norovirus symptoms and do not return to work, particularly if you work with vulnerable people or food, or send sick children to school or nursery until 48 hours after symptoms have cleared. If you have a loved one in a care home or hospital, please avoid visiting until 48 hours after symptoms have cleared,” said Lesley Larkin, surveillance lead for the Gastrointestinal Infections and Food Safety (One Health) Division at UKHSA.

“Regular handwashing is really important to help stop the spread of this bug, but remember, alcohol gels do not kill off norovirus so soap and warm water are best.”

Norovirus symptoms include severe vomiting and diarrhea that usually begin within 48 hours of exposure to the virus. Most people will make a full recovery within two to three days but it is important to drink plenty of fluids to prevent dehydration, especially for the very young, elderly or those with weakened immune systems who are more at risk.

Estimates published by the Food Standards Agency (FSA) showed that in 2018, foodborne illness cases caused by norovirus imposed the greatest societal burden at an annual cost of £1.68 billion ($2 billion) and the most illnesses with around 383,000.

Norovirus can remain infectious in foods and the environment for a long period of time and can often survive under harsher conditions than bacteria, including freezing temperatures. Outbreaks have been caused by food handlers, contaminated oysters, and fresh produce such as berries, salads, and other foods.