Almost half of working or studying participants who reported influenza-like illness in a UK symptom-monitoring programme missed work or school. Findings published on 15 October covered two winter seasons and more than 68,000 weekly symptom surveys.
The results offer a view of illness managed outside clinics and hospitals, where routine healthcare records may not capture every case. They do not mean that 47 per cent of all workers or pupils missed time, nor that every reported illness was confirmed influenza. The measure applies to participating symptom-survey users reporting influenza-like symptoms who were in work or education.
What the survey recorded
The findings draw on the 2023–24 and 2024–25 winter seasons, during which participants submitted 68,149 weekly symptom surveys. Researchers identified 1,868 influenza-like illness episodes for the analysis. Among participants in employment or education, 47.4 per cent reported missing work or school during an episode. The season-specific proportions were 46.2 per cent in 2023–24 and 49.1 per cent in 2024–25.
Most episodes were managed without contact with a healthcare service. Fourteen per cent involved contact with a service, including 6.4 per cent in which a GP was visited in 2023–24 and 9.6 per cent in 2024–25. Painkillers were the most commonly reported medication. In the 2024–25 season, three-quarters of episodes were reported to affect daily life; that measure was not available in a comparable form for the previous season.
The symptom-monitoring programme is a voluntary online system in which registered participants report symptoms each week. It is designed to capture illness among people who may stay at home rather than contact a GP, telephone service or hospital. The system complements, rather than replaces, surveillance based on laboratory tests and healthcare attendance.
Results need careful interpretation
Influenza-like illness is a symptom-based category, not a laboratory diagnosis. The study applied a standard definition based on sudden onset and a combination of systemic and respiratory symptoms. Participants were not all tested for influenza, so the absenteeism result should not be read as the proportion of confirmed flu cases missing work or school.
The study also cautions against treating the volunteer cohort as representative of everyone in the UK. Across the combined seasons, 3,057 people took part, with substantial overlap between seasons. Participants were more likely than the wider population to be female, White, aged 45 or over and retired; vaccination uptake among older participants was also higher than national rates. The researchers used weighting for age and sex in some analyses, but noted that it could not account for every difference and that self-selection and recall may leave bias.
Survey questions on effects on daily routine changed between seasons, which limits direct comparisons for that measure. The authors also note that symptom reports can be affected by how participants interpret sudden onset. These qualifications matter because the results describe the experiences of those who volunteered and reported symptoms, rather than a population-wide estimate of absenteeism.
Community monitoring as winter surveillance
The findings were publicised as the 2026–27 respiratory-virus monitoring season began. Separate surveillance published on 15 October recorded influenza activity in England remained at baseline levels in the week to 11 October, while COVID-19 activity was low and respiratory syncytial virus was increasing but also at baseline. Those indicators describe a separate reporting week and should not be confused with the older symptom-survey seasons.
The study found that the programme’s illness trends broadly tracked established influenza surveillance indicators, while also documenting illness-related behaviour beyond recorded healthcare contacts. That makes the system a complementary source of information, not proof that every symptom episode was flu or that the absenteeism proportion applies to the whole country. New participants have been invited to submit weekly symptom reports during the current winter season.
