Weekly national seasonal respiratory report
Week ending 20 November 2022 – week 46

About this release

This release is a weekly report on epidemiological information on seasonal respiratory infection activity in Scotland. Due to the COVID-19 pandemic, health care services are functioning differently now compared to previous flu seasons so the consultation rates are not directly comparable to historical data.

This is the final release in this format and the information can now be found in the Weekly National Respiratory Infection and COVID-19 Statistical Report from 30 November 2022

Main points

Overall assessment:

• The proportion of NHS24 calls for respiratory symptoms remained at Low activity level overall.
• Influenza incidence increased from Low to Moderate activity level overall.
• There were 287 influenza cases: 200 type A (subtype unknown), 38 A(H1N1)pdm09, 40 A(H3) and five nine B. This compares to 262 laboratory-confirmed cases reported during week 45.
• Seasonal coronavirus (non-SARS-CoV-2), Mycoplasma pneumoniae and Parainfluenza remained at Baseline activity level.
• Adenovirus, HMPV and rhinovirus remained at Low activity level.
• RSV remained at Moderate activity level.
• The number of laboratory-confirmed RSV cases was 269. This compares with 301 laboratory-confirmed cases in week 45.
• One NHS Board was at Baseline, five were at Low, seven were at Moderate and one was at Extraordinary activity level.
• The under 1 age group remained at Low activity level. The 1-4 age group decreased from Moderate to Low activity level. The 5-14, 45-64, 65-74 and over 75 age groups remained at Moderate activity level. The 15-44 age group increased from Moderate to High activity level.
• The majority (52.2%) of RSV detections in week 45 were in those aged under 5 years and the majority (81.1%) of diagnoses across all age groups occurred in the hospital setting.
• The hospitalisation rate for influenza has been generally increasing since week 25 and was 2.4 per 100,000 in week 45, with the highest hospital admission rate for confirmed influenza noted in patients aged less than one year old (16.5 per 100,000).  The current hospitalisation rate for influenza is lower than that for the five previous seasons prior to the COVID-19 pandemic.
• The hospitalisation rate for RSV was 2.9 per 100,000 in week 45, with the highest hospital admission rate for confirmed RSV noted in patients aged less than one year old (109.0 per 100,000). The hospitalisation rate for RSV peaked in week 38 and 39 in 2021 (4.5 per 100,000).
• In the sentinel sources (CARI), rhinovirus has been the highest circulating pathogen since the start of the season and has the highest swab positivity in week 46. This was followed by RSV which has increased from week 45.
• Influenza vaccine data for the 2022/23 winter programme are now available on the PHS flu and COVID winter vaccination dashboard. These data indicate that at the end of week 46, an estimated total of 2,035,237 individuals have received their vaccine. This includes 1,625,091 eligible adults of whom 930,500 are aged 65 years and over. In addition, 91.7% of those receiving their COVID winter booster and eligible for flu vaccine have received both vaccines at the same appointment.
• All-cause excess mortality remained at baseline activity level overall, and in all age categories.

Background

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

The spectrum of respiratory illnesses varies from asymptomatic illness to mild/moderate symptoms to severe complications including death. There is no single respiratory surveillance component that can describe the onset, severity and impact of influenza or the success of its control measures each season across a community.

This requires several complementary surveillance components which are either specific to respiratory infections or their control, or which are derived from data streams providing information of utility for other PHS specialities (corporate surveillance data). Together, the respiratory surveillance components provide a comprehensive and coherent picture on a timely basis throughout the winter respiratory season. influenza page on the HPS website (external website) for more details.

Further information

The next release of this publication will be 30 November 2022.