Norovirus cases have soared to their highest seasonal level in five years amid a nationwide surge, alarming figures suggest.
UK Health Security Agency (UKHSA) bosses received 1,237 laboratory-confirmed reports of the vomiting virus in England in April.
means cases for this time of year they are 75 percent above levels seen before Covid.
Health chiefs attributed the rise to the recent cold snap and warned people not to work for at least 48 hours after symptoms subsided.
Experts also suggested that the rise in norovirus, which can also cause diarrhoea, could be a result of Covid restrictions and new strains.
UK Health Security Agency (UKHSA) bosses received 1,237 laboratory-confirmed reports of the vomiting virus in England in April. It means cases for this time of year are 75 per cent above levels seen pre-Covid.
The illness may appear similar to Covid symptoms, with both viruses causing chills, fever and headaches.
UKHSA figures show the majority of cases were among people aged over 65.
Its data is based on positive laboratory reports and NHS hospitals reporting suspected and confirmed norovirus outbreaks. The actual number of cases will be even higher.
By contrast, there were 4,027 lab-confirmed reports at the end of January, when the bug is typically at its peak.
UKHSA norovirus epidemiologist Amy Douglas said: “Norovirus levels were higher in April than we would normally see at this time of year and have been increasing.
“This is likely due to a combination of factors, but the colder weather we have had will not have helped.”
‘Norovirus can cause dehydration, especially in vulnerable groups such as young children and elderly or immunocompromised people, so if you get sick it is important to drink plenty of fluids.
“If you have diarrhea and vomiting, you can take steps to avoid spreading the infection.”
She added: “Do not return to work, school or daycare until 48 hours after your symptoms have gone away, and do not prepare food for others during that time.”
‘If you are unwell, avoid visiting people in hospitals and nursing homes to avoid spreading the infection in these settings.
Washing your hands with soap and warm water and using bleach-based products to clean surfaces will also help stop the spread of infection.
“Alcohol gels do not kill norovirus, so don’t rely on them alone.”
Experts today suggested that Covid restrictions could also be partly to blame for the current surge, as fewer people have been exposed to norovirus than usual since the start of the pandemic.
According to their theory, our bodies may be less equipped to fight infection after years with little exposure to them.
The same reason was partly attributed to the unprecedented increase in scarlet fever cases, which in 2022 skyrocketed to the highest number recorded since the 1950s.
But they also warned that new strains of the virus could be behind the surge.
Professor Adam Finn, a member of the Government’s vaccine advisory panel at the University of Bristol, told MailOnline: “The recent higher-than-usual figures may still be linked, at least in part, to the drop in numbers over the Covid lockdown period.”
‘We continue to see unusual epidemiology in terms of number of cases and seasonality of numerous infections, after the pandemic.
“The relatively bad weather during the spring may also have contributed.
‘Sometimes we see the emergence of new strains of norovirus against which people have little or no immunity due to previous infections.
‘About 17 percent of the most recent cases are due to a strain called G.II.17 that has emerged very recently. Therefore, this may also contribute to the number of cases being higher than usual.’
He added: “There are also vaccines on the horizon and one is about to announce results from a phase three trial.”
“Therefore, we may have the tools to prevent or at least reduce this problem in the not-too-distant future.”
Meanwhile, Dr David Allen, associate professor of virology at the London School of Hygiene and Tropical Medicine, told MailOnline that the “unseasonal rise” in cases “is an interesting and important observation”.
He added: ‘Norovirus is a diverse group of viruses with many different types.
Experts today suggested that Covid restrictions could also be partly to blame for the current surge, as fewer people have been exposed to norovirus than usual since the start of the pandemic. According to their theory, our bodies may be less equipped to fight infection after years with little exposure to them.
“People can get norovirus many times because infection with one type of norovirus may not protect against the other types, and protective immunity after infection may not be long-lasting.”
He said: “There is a lot we still don’t understand about how people respond to norovirus infection and how responses to one type of norovirus relate to others.”
‘Other important factors are that we still do not fully understand the ongoing changes in norovirus epidemiology following the Covid pandemic.
“Changes in patterns of sampling, testing, and reporting to national surveillance systems can influence data in ways that are difficult to monitor.”
Norovirus can increase pressure on hospitals because infected patients must be isolated in individual rooms or wards must be closed to new patients to contain the spread.
Symptoms include nausea, vomiting and diarrhea, while some patients may also have fever, headache and pain in the arms and legs.
Most people improve within two to three days and can manage their condition at home by resting and drinking plenty of fluids.
However, in severe cases, some people may need to be hospitalized, and the elderly and children are most at risk.