HPA update on seasonal norovirus activity: 28 December 2012

28 December 2012

Latest figures from the Health Protection Agency (HPA) show there have been 3,538 laboratory confirmed cases of norovirus this season (from week 27 to week 50 2012), up from 3,046 cases last week. The latest figures are 83 percent higher than the number of cases reported at this point last year (the same increase as was reported last week), when there were 1,934 cases.

During the two weeks up to 23 December there were 70 hospital outbreaks reported, compared to 61 in the previous fortnight, bringing the total of outbreaks for the season to 538.

The distribution of norovirus cases across the season varies significantly from year to year, but the number of cases has risen earlier than expected this year. It has not yet been determined why this has been the case, but it is a trend that has been seen across Europe and other parts of the world.

John Harris, an expert in norovirus from the HPA said: “The number of laboratory confirmed cases has risen once again as it appears that we have seen the rise in cases that usually begins in January start a little earlier than we normally expect.

“Norovirus is very contagious, and very unpleasant. To help prevent spread of the disease, it’s important that people who believe they are unwell with the virus maintain good hand hygiene and stay away from hospitals, schools and care homes, as these closed environments are particularly prone to outbreaks which can cause severe disruption.”

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.

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Notes for 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 health care 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].
The latest norovirus report can be found at the HPA Norovirus page.
Figures show that there were 287 laboratory confirmed cases of norovirus on November 11 2012 (week 45 and November 18 2012 (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 [external link].
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: 28 December 2012