Friday, February 11, 2011

UK: HPA Weekly Influenza Surveillance

 

 

 

#5305

 

After an extremely active December, influenza activity in the UK has been on the decline now for several weeks, and currently rests below the baseline level. 

 

As busy as it was, the chart below indicates that the 2010-2011 winter epidemic (red) didn’t come close to matching the deadly epidemic of 1999-2000 (blue).

 

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Which isn’t to suggest that the UK had an easy time of it this winter. As the chart below illustrates, with the exception of the pandemic of 2009, this winter has been the worst `flu season’ in a decade.

 

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These, and many other flu graphics, are available from HPA Weekly National Influenza Graphs (PDF, 687 KB)

 

This week’s HPA influenza activity summary follows:

 

 

Report published 10 February 2011

Summary

Influenza activity continues to decline in the UK.  GP consultation rates are below baseline levels in England, Wales, Scotland and Northern Ireland. All influenza types are reducing, with influenza B now the predominant virus; influenza A H1N1 (2009) continues to circulate, with very few, sporadic influenza A (H3N2) virus detections.  The H1N1 (2009) virus strain is virologically and epidemiologically similar to that seen during the pandemic.  The virus strains circulating are overall well matched to the current influenza vaccine.

  • In week 5 (ending 6 February) the weekly ILI consultation rate decreased in England (23.6 per 100,000), Wales (13.2 per 100,000) and Northern Ireland (69.6 per 100,000) and remained constant in Scotland (45.7 per 100,000).
  • The weekly national proportions of NHS Direct calls for cold/flu and fever have decreased.
  • One acute respiratory disease outbreak was reported in the UK in week 5 in a primary school.  This brings the total reported this season so far to 169. 
  • Twenty-two of 111 (19.8%) specimens from patients with ILI presenting to sentinel GPs in England in week 5, were reported as positive for influenza.  The proportion of specimens reported to DataMart (England) as positive for influenza decreased to 7.4% (94 of 1,275).  The proportion of samples positive for RSV remained stable, the proportion positive for rhinovirus increased and was low for parainfluenza, adenovirus and HMPV. 
  • Since week 36, 439 confirmed UK deaths associated with influenza infection have been reported.  Excess all-cause mortality is now below the upper limit of expected levels for this time of year in week 4.
  • By week 5, the proportion of people in England aged over 65 years who had received the 2010/11 influenza vaccine was 72.2%. For those in a risk group aged under 65 years it was 50.0%. Amongst frontline health-care workers the provisional uptake was 26.1% by 31 December 2010.
  • In Europe, many countries continue to report regional or widespread, medium to very high influenza activity. Trends are starting to decrease in some earlier affected countries, while others continue to increase: four countries have raised intensity from medium to high for the first time this season.  Influenza A H1N1 (2009) continues to be predominant in Europe, but over 30% of influenza detections recently were influenza B.  Influenza activity appears to have peaked in much of the temperate northern hemisphere with variable predominance of H1N1 (2009), H3N2 and influenza B.