Weekly national seasonal respiratory report
Week 25 2021

About this release

This release is a weekly report on epidemiological information on seasonal influenza activity in Scotland. Due to COVID health care services are functioning differently now compared to previous flu seasons so the consultation rates are not directly comparable to historical data.

Main points

• The rate of influenza-like illness (ILI) was at Baseline activity level (0.5 per 100,000).
• The swab positivity of influenza was at Baseline activity level (0.0%, 0/2543).
• The incidence rate of influenza was at Baseline activity level (0.0 per 100,000 population).
• There were no influenza cases reported this week. The low numbers of influenza may be related to current restrictions and an increased uptake of flu vaccine, combined with end of influenza season. However, data are provisional and may be subject to change.
• The proportion of total NHS24 calls for respiratory symptoms remained at Low (16.8% - <20.8%) activity level. NHS24 calls for 5-14 year age group increased to Low (26.6% - 29.7%) activity level and for the 15-44 year age group remained at Low (9.7 - <12.0%) activity level. Calls for <1 year age group remained at Moderate (50.6% - <59.7%) activity level. For those aged 1-4 years, calls for respiratory symptoms (67.8%) remained at Extraordinary (>=66.7%) activity level.
• Parainfluenza remained at Extraordinary (>=1.6 per 100,000 population) activity level with 96 cases (1.8 per 100,000 population). All other non-flu pathogens remained at Baseline activity level.
• Influenza vaccine uptake up to end of week 15 in Scotland has been finalised; in most eligible cohorts this was observed to be higher than in previous seasons, although the data are not directly comparable.

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 complementary surveillance components which are either specific to influenza or its control, or which are derived from data streams providing information of utility for other PHS 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 HPS website (external website) for more details.

Further information

The next release of this publication will be 7 July 2021.