HPA update on seasonal norovirus activity

4 December 2012

Figures from the Health Protection Agency (HPA) show a drop in the number of hospital outbreaks of norovirus from 53 in the two weeks to November 25 2012 down to 40 in the two weeks to the 2 December 2012. The latest weekly report is now published.

However, the total number of confirmed laboratory reports of norovirus (both from community and hospital cases) is 2,313 for the season which is 64 per cent higher than the same period in the last season when there were 1,412 cases reported. There are no clear indications as to why activity is higher this year.

The laboratory confirmed reports only represent a small proportion of the actual amount of norovirus activity in the community and it is estimated for every confirmed case there are a further 288 unreported cases*.

As part of the HPA’s surveillance of norovirus it collects data from NHS Direct. Analysis of calls into the service show that the proportion of calls for diarrhoea are stable and within seasonally expected levels. Those relating to vomiting are decreasing but are still higher than the usual levels seen at this time of the year.

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

Its symptoms 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.

Dr Bob Adak, head of the gastrointestinal diseases department at the HPA said: “The norovirus season is always completely unpredictable as it peaks and falls over several months – usually October to April. However, one thing we do know is that every year we will see a large amount of norovirus activity because it is highly contagious.

“The figures for the last two weeks show that there has been a reduction in the numbers of outbreaks in hospitals although there are clearly a lot of other people becoming unwell as we can see from the number of lab reports. We would like to remind people to avoid visiting friends or relatives in hospital or care homes if they have symptoms consistent with a norovirus infection as it can lead to ward closures and severe disruption.

“Norovirus is a short-lived unpleasant infection but most people will fully recover in a couple of days. It is important to remain hydrated as you will be losing a lot of fluids due to the symptoms. 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 visit the NHS Direct website [external link].
• 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 to Editors

1. *Data from The Infectious Intestinal Diseases II (IID II) report can be found at the Food Standard Agency website [external link].
2. The latest norovirus report can be found at the HPA Norovirus page.
3. 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 [external link].
4. 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: 4 December 2012