If it seemed that a lot of people were ill over Christmas, that's because they were. Blame a little thing called norovirus, writes Fiona McCann
Did it seem that more than the average share of friends and family were laid low over the Christmas period this year? For once, anecdotal evidence tallies with the official statistics as new figures reveal the numbers coming down with stomach bugs this winter have been on the up.
According to the latest data from the Health Protection Surveillance Centre (HSPC), there's been a substantial increase in cases of norovirus, or winter vomiting disease, the symptoms of which include sudden vomiting and diarrhoea.
"Regarding norovirus, we're in a period of pretty high activity and we've been in a period of high activity since mid-November," says Dr Paul McKeown, a consultant with the HPSC, who describes the disease as "the stomach and bowel equivalent of the common cold". According to Dr McKeown, the number of cases being reported are the highest since 2004. "What we've been seeing recently on a weekly basis is as high as we've seen in the last three years," he says. "The big question is whether this will be sustained, whether there is a slightly new version of the bug around with sufficiently few people with immunity to it ensuring that it will be spread relatively quickly. It's increasingly looking very likely that it will be prolonged." In the UK, the Health Protection Agency (HPA) says the number of norovirus cases reported this year surpasses all other recent years except 2002, which was the most severe season recorded due to the emergence of a new virus strain.
But the agency suggests that the elevated figures could also be due to a new testing system that ensures more cases are being diagnosed and reported than ever before. "We have a new test that has been brought out, which is being used to pick up norovirus infections better," a spokesperson for the HPA told The Irish Times. "We're not seeing a new strain, which is good, and it's not an epidemic so to speak, so it does suggest better awareness and better testing."
In Ireland, Dr McKeown says virus levels are not yet as high as in 2002, when a major upsurge was recorded, but they are "well up there with 2004, which was considered a minor upsurge year". He advises those who have caught the bug to drink plenty of fluids, and stay away from alcohol and food until the stomach has settled, and warns that norovirus is highly infectious and easily transmitted by sufferers.
"It takes a very small amount of virus particles to cause illness," says Dr McKeown. "Whenever somebody with norovirus vomits there would be anything between 30 and 50 million virus particles in their vomit, and it only takes five or 10 particles to make you sick, so it's very infectious. These viruses can also last for over a fortnight on carpets and surfaces."
With this in mind, Dr McKeown advises scrupulous cleanliness to minimise infection. "Where somebody has vomited, it's very important that whoever is cleaning up afterwards cleans the area well using a warm bleach solution to wipe down hard surfaces such as toilet seats, tiled floors etc, and that everybody washes their hands frequently with warm water and soap."
Despite its intense symptoms, however, the disease tends to be shortlived, and many recover within days.
"In general you only vomit half a dozen times, and after a day or so you're completely well," says Dr McKeown, who cautions those who have come down with the bug to stay at home for at least 48 hours after symptoms have disappeared to avoid spreading the virus.
"There's a large body of evidence that suggests people are still highly infectious for two days afterwards, and we insist that they remain out of action for 48 hours after their symptoms are gone. It may seem daft to an employer to have somebody sitting at home who has no symptoms, but insisting on people coming back within that 48-hour window is a false economy, because they will almost certainly bring the virus back into the workplace with them." Dr McKeown does warn, however, that not every gastric upset indicates the presence of norovirus. "You have to bear in mind that it was Christmas time and people were challenging their alimentary systems with alcohol and with food," he says. "People can overdo it."