Norovirus – Credit HPA
# 6817
The UK’s HPA has released a new update on their busy norovirus season, which has prompted headlines in British papers announcing more than One Million Cases this year.
That number is an extrapolation, based on the assumption that there are 288 uncounted cases for every case officially diagnosed.
So take it as an estimate, not a precise count. Still, reported cases of norovirus are well ahead of last year’s numbers across the UK.
HPA update on seasonal norovirus activity: 2 January 2013
2 January 2013
Latest figures from the Health Protection Agency (HPA) show there have been 3,877 laboratory confirmed cases of norovirus this season (from week 27 to week 51 2012). The latest figures are 72 per cent higher than the number of cases reported at this point last year, when there were 2,255 cases.
During the Christmas period there is typically a drop in the number of laboratory reports. In previous norovirus seasons the general trend is that cases increase in the New Year and we expect to see cases rise again over the next few weeks.
During the two weeks up to 30 December there were 29 hospital outbreaks reported, compared to 70 in the previous fortnight, bringing the total of outbreaks for the season to 590.
Cases of norovirus have risen earlier than expected this winter season and this is a trend that has been seen across Europe and other parts of the world. It has not yet been determined why this has been the case and activity varies significantly from year to year.
John Harris, an expert in norovirus from the HPA said: “As we have seen in previous years there has been a dip in the number of confirmed laboratory reports owing to the Christmas and New Year period. However, in line with other norovirus seasons we will expect to see an increase in the number of laboratory reports in the next few weeks.
“Norovirus is very contagious, and anyone who has had it knows it is very unpleasant. If you think you may have the illness then it is important to maintain good hand hygiene to help prevent it spreading. We also advise that people stay away from hospitals, schools and care homes as these environments are particularly prone to outbreaks.”
Norovirus can be transmitted by contact with contaminated surfaces or objects, by contact with an infected person, or by the consumption of contaminated food or water. Symptoms of norovirus include a sudden onset of vomiting and/or diarrhoea. Some people may have a temperature, headache and stomach cramps. The illness usually resolves in one or two days and there are no long-term effects.
Ends
Notes to editors
- Indications from Europe and Japan are that norovirus activity also started to increase early. In Australia the norovirus season also peaks during the winter but this season it has gone on longer than usual and they are seeing cases into their summer. The HPA is following up with colleagues internationally.
- The number of laboratory confirmed cases represents just a fraction of the actual amount of norovirus activity as it is estimated that for each confirmed case, there are a further 288 unreported cases, as the vast majority of those affected do not seek healthcare services in response to their illness. Data from The Infectious Intestinal Diseases II (IID II) report can be found at the Food Standards Agency website [external link].
For more on noroviruses, you may wish to revisit the following blogs.
Vomiting Larry And His Aerosolized Norovirus
An Unwanted Lagniappe From The Kitchen
UK: Norovirus Season Starts Early
