HPA update on seasonal norovirus activity

12 December 2012

Figures from the Health Protection Agency (HPA) show that in the two weeks ending December 2 there has been a 28 per cent reduction in the number of confirmed lab reports of norovirus.

During the week ending November 25 there were 327 confirmed cases and 236 during the week ending December 2. The latest weekly report is published today.

The figures for the number of hospital outbreaks show that there were 45 hospital outbreaks during the last two weeks up to December 9. This is similar to the previous fortnight to December 2.

In this season to date there have been 2,630 confirmed laboratory reports of norovirus. This is 72 per cent higher than the same period in the last season when there were 1,533 cases reported. There are no indications as to why activity is higher this year.

Laboratory confirmed reports represent only a small proportion of the actual amount of norovirus activity in the community, because the vast majority of affected people do not access health care services as a result of their illness. It has been estimated that for every confirmed case there are around 288 unreported cases*.

As part of the HPA’s surveillance of norovirus data are collected from various sources including NHS Direct. Analysis of calls to NHS direct show that the proportion of calls for diarrhoea and vomiting are stable and within seasonally expected levels.

Norovirus is highly contagious and can be transmitted by contact with an infected person; by contact with contaminated surfaces or objects or by consuming contaminated food or water. The virus spreads rapidly in closed environments such as hospitals, schools and care homes.

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.

John Harris, an expert in norovirus at the HPA said: “Our figures show a small drop in the number of confirmed cases over the last couple of weeks. We cannot read too much into this at present as this is typical of the norovirus season where we see a series of sharp rises and falls in activity between October and April with the bulk of cases usually occurring between January and March.

“People should be vigilant in their hygiene and we would like to remind anyone who has typical symptoms suggestive of norovirus infection to avoid visiting friends or relatives in hospital or care homes. Norovirus infection in hospitals is very disruptive as it can lead to ward closures.

“Having a norovirus infection is very unpleasant but it is short-lived and most people will fully recover in a couple of days. Make sure that you or anyone you are caring for takes plenty of fluids to avoid dehydration. Over-the-counter medicines can also be useful in reducing headaches and other aches and pains”.

Advice for the public when managing a bout of norovirus:

Do not visit your GP surgery or local A&E Unit. Norovirus infection is a self-limiting illness and you will recover naturally without treatment. It is, however, important to take plenty of drinks to replace lost fluids.
Use NHS Direct's new diarrhoea and vomiting online health and symptom checker, to get advice on how to manage your symptoms at home or help to access the most appropriate health service: https://www.nhsdirect.nhs.uk/CheckSymptoms/SATs/DandV5AndOver.aspx
Wash hands thoroughly and regularly at all times, but particularly after using the toilet and before eating.
Do not visit friends or relatives in hospitals or residential care homes as there is a real risk that you would introduce the infection putting vulnerable people at risk.

ENDS

Notes for editors:

*Data from The Infectious Intestinal Diseases II (IID II) report can be found here: http://www.food.gov.uk/science/research/foodborneillness/foodbornediseaseresearch/
b14programme/b14projlist/b18021/#.ULzDFiKPWHc
The latest norovirus report can be found here: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/Norovirus/
Figures show that there were 287 laboratory confirmed cases of norovirus in the week ending November 11 (week 45) and during the ending November 18 (week 46) there were 316 cases.
The Health Protection Agency is an independent UK organisation that was set up by the government in 2003 to protect the public from threats to their health from infectious diseases and environmental hazards. In April 2013, subject to the usual approvals procedures for establishing new bodies, the Health Protection Agency will become part of a new organisation called Public Health England, an executive agency of the Department of Health. To find out more, visit our website: http://www.hpa.org.uk or follow us on Twitter @HPAuk or ‘Like’ us on Facebook at www.facebook.com/HealthProtectionAgency
For more information please contact the national HPA press office at Colindale on 0208 327 7901 or email colindale-pressoffice@hpa.org.uk. Out of hours the duty press officer can be contacted on 0208 200 4400.

Last reviewed: 12 December 2012