Collection

Seasonal influenza: guidance, data and analysis

The symptoms, diagnosis, management, surveillance and epidemiology of seasonal influenza (flu).

Published 14 July 2014
Last updated 6 November 2019 — see all updates

• From: Public Health England

Influenza (flu) is a viral infection affecting the lungs and airways. The symptoms can appear very quickly and include:

• headache
• fever
• cough
• sore throat
• aching muscles
• joints

Complications include bacterial pneumonia, and can be life threatening especially in:

• older people
• those with certain underlying health conditions

It occurs most often in winter in the UK and peaks between January and March.

There are 2 types of influenza affecting people:

• influenza A
• influenza B

Influenza B usually causes a milder illness, and is most seen in children.

Information on the different strains of influenza virus can be found on our health protection archive website.

Seasonal influenza risk assessment for 2015 to 2016, for countries in the EU/EEA can be downloaded from the ECDC website

Annual flu programme

Vaccination of at risk groups and children can offer some protection against infection. The NHS plans each year for the demands of flu across England in its annual flu programme.

See Latest vaccine uptake guidance and the latest coverage for figures on seasonal flu vaccination rates.

Diagnosis, management and treatment

• Amantadine, oseltamivir and zanamivir (Relenza) for the treatment of influenza National Institute for Health and Clinical Excellence (NICE) technology appraisal 168, February 2009.

• Oseltamivir, amantadine (review) and zanamivir for the prophylaxis of influenza NICE technology appraisal 158, September 2008.

1. Point of care tests for influenza and other respiratory viruses
   • 28 October 2019
   • Guidance
2. Influenza-like illness (ILI): managing outbreaks in care homes
   • 15 October 2018
   • Guidance
3. Influenza-like illness (ILI): managing outbreaks in schools
   • 26 September 2019
   • Guidance
4. Seasonal influenza: managing cases in critical care units
   • 22 November 2019
   • Guidance
5. Influenza: treatment and prophylaxis using anti-viral agents
   • 8 October 2019
   • Guidance
6. Respiratory tract infections: infection control
   • 2 November 2016
   • Guidance

Epidemiology

National and international partners work with PHE to track influenza’s spread and effect on health worldwide:

• Health Protection Scotland: respiratory infections
• Public Health Agency, Northern Ireland: seasonal influenza
• Public Health Wales: weekly flu activity in Wales
• European influenza surveillance network
• World Health Organization: seasonal influenza

1. Weekly national flu reports: 2019 to 2020 season
   • 5 December 2019
   • Official Statistics
2. Weekly national flu reports: 2018 to 2019 season
   • 26 September 2019
   • Official Statistics
3. Weekly national flu reports: 2017 to 2018 season
   • 27 September 2018
   • Official Statistics
4. Annual flu reports
   • 30 May 2019
   • Official Statistics
5. Sources of UK flu data: influenza surveillance in the UK
   • 30 September 2019
   • Guidance

Respiratory Virus Unit services and guidance for laboratories

The Respiratory Virus Unit (RVU) provides laboratory services for respiratory infections including influenza. Further information and guidance is available on RVU services.

1. Referring influenza samples to PHE respiratory virus unit
   • 15 October 2019
   • Guidance

Antiviral resistance

1. Influenza: antiviral susceptibility surveillance and diagnosis of resistance
   • 20 November 2018
   • Guidance

Data submission

The winter health watch summarises findings from the surveillance systems that track reported flu, norovirus, and rotavirus levels, and syndromic surveillance findings through the winter season.

1. Acute respiratory infection outbreak: reporting form
   • 28 November 2019
   • Form

Published 14 July 2014
Last updated 6 November 2019 + show all updates

1. 6 November 2019 Added weekly national flu report for 2019 to 2020 season.
2. 28 November 2018 Added 'Point of care tests for influenza and other respiratory viruses'.
3. 11 October 2018 Added 'weekly national flu reports: 2018 to 2019 season' to the collection.
4. 8 October 2018 Added 'Influenza-like illness (ILI): managing outbreaks in schools'.
5. 2 August 2017 Added 'Seasonal influenza: managing cases in critical care units' under management and treatment section.
6. 9 February 2016 Web link added for seasonal influenza risk assessment (2015-2016) for countries in the EU/EEA.
7. 14 July 2014 First published.