Weekly national seasonal respiratory report
Week 11

About this release

This release is a weekly report on epidemiological information on seasonal influenza and other seasonal respiratory infections activity in Scotland.

Main points

Overall assessment

• Influenza activity is showing signs of decreasing with almost all indicators suggesting falling activity. There remains evidence of circulation of influenza within the community and closed settings. The syndromic surveillance indicators show increased activity in the past week which is likely to be attributed to COVID-19. A CMO letter (external website) was issued in week 49 advising that GPs may prescribe antivirals.
• A Scottish addendum to the Public Health England guidance on use of antiviral agents for the treatment and prophylaxis of seasonal influenza has been published.

In week 11

• The rate of influenza-like illness (ILI) was at Low activity level (27.6 per 100,000).
• The proportion of NHS24 respiratory calls was at Extraordinary activity level (48%).
• The swab positivity of influenza in primary care was at Baseline activity level (5.6%, 2/36).
• The swab positivity of influenza in secondary care was at Baseline activity level (6.0%, 171/2,852).
• The incidence rate of influenza in secondary care was at Baseline activity level (3.4 per 100,000 population).
• The number of new acute respiratory illness outbreaks with onset in week 11 was at Baseline activity level (n=0).
• The number of new SARI cases admitted to ICU during week 11 was at Baseline activity level (n=0). There was one new SARI death reported. The SARI case-fatality rate (CFR) reported since week 40 2019 was 18.7% (14/75) and remains below expected seasonal levels (range 22.9% - 35.6%).
• The all-cause mortality excess for “all ages” was at Baseline activity level in week 9.

Background

Surveillance of influenza infection is a key public health activity as it is associated with significant morbidity and mortality during the winter months, particularly in those at risk of complications of flu e.g. the elderly, those with chronic health problems and pregnant women.

The spectrum of influenza illness varies from asymptomatic illness to mild/moderate symptoms to severe complications including death. In light of the spectrum of influenza illness there is a need to have individual surveillance components which provide information on each aspect of the illness.

There is no single flu surveillance component that can describe the onset, severity and impact of influenza or the success of its control measures each season across a community. To do so requires a number of complimentary surveillance components which are either specific to influenza or its control, or which are derived from data streams providing information of utility for other HPS specialities (corporate surveillance data). Together, the influenza surveillance components provide a comprehensive and coherent picture on a timely basis throughout the flu season.

Please see the influenza page on the website (external website) for more details.

Further information

The next release of this publication will be 26 March 2020.