Wednesday 16 January 2013

Norovirus

Onto one of the biggest media stories that was reported on around Christmas time. Norovirus or the 'winter vomiting bug' was responsible for a large number of dramatic media headlines over the winter period with a BBC headline entitled "winter vomiting cases at 1.1 million", described by some as an outbreak, others as a superbug...but really? I for one don't know anyone who contracted norovirus this year yet the stats presented by the media corporations are very dramatic as if no-one is untouched by it?

The Health Protection Agency (HPA) (http://tinyurl.com/b9xw4gb) has up to date information on the number of laboratory cases reported of norovirus in England and Wales in each year from the year 2000 up to 2012 (but the 2012 data is at the moment provisional).

Laboratory reports of norovirus in England and Wales 2000-2012
 
 
This graph, from the HPA website, shows the number of laboratory reports in each year (for precise figures see the URL above). Between 2000 and 2005 the levels fluctuated but rose steadily from 2005 to 2009 and then steeply in 2010. Since 2010 there have been large fluctuations in the number of reports and it will be interesting to see the levels in 2013.
 
In 2010 there was also a media storm about norovirus, once again being described as a pandemic and a superbug (this would presumably be down to the increase that can be observed in the graph above). The big issue in 2011 was to do with "norovirus being found in 76% of British oysters" (http://tinyurl.com/c5rb6ns).

Information at http://www.patient.co.uk/doctor/Norovirus.htm tells you all you need to know about norovirus but I will pick out the useful parts;

"Noroviruses (NVs) are a genus of the Caliciviridae family of viruses found in 'used' water. They are concentrated in shellfish, oysters and plankton."

"The numbers [of cases] seem to have risen since about 1993 and this may in part be spurious due to the introduction of a commercially available enzyme-linked immunosorbent assay (ELISA) test that made diagnosis much easier. However, it may also be due to the emergence of a new strain of NV which is even more virulent [infectious] than the original strain."

"Outbreaks tend to affect no more than about 50% within a community. Outbreaks tend to be within November to April when pressures on hospitals are at their greatest." This therefore indicates an issue with infection control within hospitals when there is great pressure/the capacities are high; such as the use of alcohol gels and the ability to isolate those with the virus.
  
"There is a risk of mortality especially in the frail, immunocompromised [where the immune system is unable to respond effectively] and at the extremes of age."

A headline reading "winter vomiting cases at 1.1 million" is definitely an alarming headline to read. But as we can see from the data in the above graph and the detailed values on the HPA website their cases are nowhere near the 1 million mark (only just reaching 10,000).

The 1.1 million value has therefore been quoted on the basis 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" (http://tinyurl.com/ae3a4xa). So based on the current 4,407 number of laboratory cases reported (as of yesterday rather than the BBC's report on the 2 January) the total number of cases is at 1,273,623 across England and Wales. So maybe the ground shaking figures on the BBC news website are relevant but still may not be completely accurate as 288 is only a rough guide to the levels of undiagnosed norovirus.

"John Harris, an expert in norovirus from the HPA said: “Norovirus activity always varies from year to year and although we might have expected cases to rise again now we have passed the New Year period this hasn’t been the case. We can’t read anything into this fall and don’t know how busy the rest of the season will be. The busiest months are normally from December to April, so further cases will occur but we can’t say if there will be further significant increases in the number of laboratory reports.

“There have been reports in the media of people with symptoms of norovirus attending their local hospital but we would urge people not to do this. If you think you may have the illness then it is important to stay away from any healthcare facility and care homes to avoid spreading it to people who may have underlying health conditions and already be vulnerable” (http://tinyurl.com/ae3a4xa).

But there is no need to worry, not as the NHS was  provided with "additional funding to help it cope with the added pressure that the winter brought" but also the statement from the Department of Health in England who "said 2.4% of beds were closed in the NHS due to norovirus symptoms compared with a peak of 2.9% last year." (http://www.bbc.co.uk/news/health-20889382)

Maybe we should just follow Charlie Brooker in his suggestion?
"If things go disastrously wrong, and you've shaken someone's revolting disease-sodden hand and you don't have immediate access to hot water and a sink, it's imperative to remember your hand is "evil" until you've had a chance to wash it. Don't eat with it, and don't pick your nose or rub your eye with it either or you will die. Keep it in a pocket. Or sit on it... Just don't use it. Now wash your hands." (http://tinyurl.com/bccsg7t

No comments:

Post a Comment