Viral respiratory diseases (including influenza and COVID-19) in Scotland surveillance report

5th January 2024

About this release
This weekly release by Public Health Scotland presents epidemiological information on respiratory infection activity, including COVID-19, across Scotland. Due to the dynamic nature of all datasets included in this report, figures contained within each update may be subject to change in future releases. Any revised figures will then be reflected within the latest update.

Main points
Overall assessment 25 December 2023 to 31 December 2023 (ISO week 52):

Measures of respiratory symptoms in the community show Low activity level (via calls to NHS24) and Baseline activity level (via attendances at GP consultations - GP ILI) during the reporting period.
In the CARI community surveillance system, RSV showed the most notable increase in swab positivity rate, rising from 8.3% in week 51 to 12.4% in week 52. Influenza A increased from 20.4% to 24.1%, establishing itself as the most dominant circulating virus. Rhinovirus—previously the most prevalent pathogen this season—declined from 19.2% to 13.4%.
Virology data showed influenza increased to High activity level in week 52. Moderate or High activity levels were observed among all age groups. Swab positivity for influenza was 14.9% in week 52 compared to 12.9% in week 51. RSV decreased from Moderate to Low activity level and Mycoplasma pneumoniae decreased from High to Moderate activity level.
Emergency hospital admissions because of influenza increased from 341 to 436, and for COVID-19, from 331 to 375. In contrast, RSV decreased from 204 to 176. ICU/HDU admissions increased for influenza but remained low for RSV and COVID-19.
All-cause excess mortality for week 49 (week ending 10 December 2023, the latest week not impacted by reporting delays) remained at Baseline activity level overall, and for all age groups.
In winter 2023/24, Scotland administered 1,634,736 Influenza (Adult 18+), 532,275 influenza (Children 6 months to 17 years), and 1,376,823 COVID-19 vaccines since September 4, 2023. Among adults 65+, 79.1% got influenza, and 78.4% got COVID-19 vaccines by week 52. Uptake is lower for influenza and COVID-19 vaccines compared to winter 2022/23.
Background
Tracking infectious respiratory diseases, including COVID-19 and influenza, is essential, especially in the winter when the disease burden can be highest. In Scotland, respiratory infection and associated morbidity are monitored using enhanced surveillance. This approach combines data from microbiological sampling and laboratory test results from community and hospital settings with data from syndromic surveillance of NHS 24 calls, primary care consultations for respiratory symptoms, hospital (including intensive care) admissions and other settings.

The intelligence generated from surveillance of laboratory, syndromic and community settings provide a comprehensive picture of current respiratory illness in Scotland. The data presented in this report provide a comprehensive and timely epidemiological picture that is essential for understanding transmission of infection and supporting patient care and NHS service planning and policy.

Seasonality patterns / seasonal variations
Respiratory illnesses are associated with seasonal increase in the autumn and winter. Seasonality patterns for both influenza viruses and non-influenza respiratory pathogens have been established through many years of surveillance data. Most influenza and non-influenza pathogens circulate in the autumn and winter in Scotland, although some are known to circulate in the spring and summer. Notably, COVID-19 transmission has been occurring in waves throughout the year as observed from surveillance data since the start of the pandemic in 2020.

Further information
The next release will be on 11 January 2024.

For more information go to https://publichealthscotland.scot/