Flu cases across Scotland nearly double as new strain spreads

The number of flu cases in Scotland almost doubled in a week, with figures showing a significant increase in hospital admissions.

Public Health Scotland (PHS) reported that laboratory-confirmed flu cases have increased by 45%, from 555 to 805, in the week up to November 23, while hospital admissions jumped from 279 to 391.

Test positivity also rose sharply, from 11.0% to 15.8%, marking a level of influenza activity not typically seen this early in the season.

Health officials say that all age groups are affected, which is not typical of the time of year.

This is down to a mutation of the H3N2 strain of influenza. It is known for causing more severe illness, particularly among older adults.

This year, most infections are due to the influenza A(H3N2) strain – in previous years influenza A(H1N1) has been more frequently detected.

Data from the Community Acute Respiratory Infection (CARI) primary care surveillance system shows the virus driving nearly a quarter (22.8%) of all acute respiratory infection consultations.

While flu numbers have climbed, other respiratory pathogens remain relatively stable.

RSV (respiratory syncytial virus) levels stayed low compared with last season, though hospital admissions nudged up from 118 to 138. Covid-19 activity either fell or held steady, with 60 hospital admissions, down from 79 the previous week.

Activity for adenovirus, parainfluenza and rhinovirus remained low, with rhinovirus test positivity falling to 30.1% over the most recent four-week period.

Public Health Scotland noted that, although GP consultations for influenza-like illness have fallen overall to baseline levels, children aged between five and 14 continue to see medium-level activity.

NHS24 also recorded an increase in calls for respiratory symptoms, though still at a low level.