Seasonal influenza

HPA national influenza report — Summary of report published 27 January 2011

Influenza activity is declining in the UK. GP consultation rates remain above baseline levels in England, Wales and Northern Ireland. The predominant influenza virus is now influenza B; influenza A H1N1 (2009) continues to be detected, 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 3 (ending 23 January) the weekly ILI consultation rate decreased England (40.7 per 100,000), Wales (26.9 per 100,000) and Northern Ireland (126.2 per 100,000), while a slight increase was observed in Scotland (47.9 per 100,000)
• The weekly national proportions of NHS Direct calls for cold/flu and fever have decreased.
• Twelve acute respiratory disease outbreaks were reported in the UK in week 3, two in care homes, two in prisons and eight in schools. This brings the total reported this season so far to 165.
• Twenty-eight of 186 (15.1%) specimens from patients with ILI presenting to sentinel GPs in England in week 3, were reported as positive for influenza. The proportion of specimens reported to DataMart (England) as positive for influenza decreased to 13.5% (267 of 1,942). The proportion of samples positive for RSV and rhinovirus increased and was low for parainfluenza, adenovirus and HMPV.
• Since week 36, 338 UK deaths associated with influenza infection have been reported. Excess all-cause mortality continues to be observed in week 2.
• By week 3, 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 49.1%. Amongst frontline health-care workers the provisional uptake was 26.1% by 31 December 2010.
• In Europe, most countries are reporting regional or widespread influenza activity, with medium to very high influenza-like illness/acute respiratory infection (ILI/ARI) consultation rates and increasing trends, primarily associated with influenza A H1N1 (2009). In North America, influenza activity has decreased; influenza A (H3N2) and B viruses continue to be predominant.
• Reports of seasonal influenza activity are published by the Health Protection Agency from October to April.

H1N1 influenza

For information on H1N1 influenza ('swine flu'), see:

• Swine fever (HPA).
• Clinical guidelines for patients with an influenza like illness during an influenza pandemic (British Infection Society, British Thoracic Society, HPA in collaboration with the Department of Health).
• Swine flu clinical package (Department of Health).