Developing influenza and respiratory syncytial virus activity thresholds for syndromic surveillance in England

Sally Harcourt*, Roger Morbey, Gillian Smith, P. Loveridge, Helen Green, Richard Pebody, J. Rutter, F. A. Yeates, G. Stuttard, Alex Elliot

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Influenza and respiratory syncytial virus (RSV) are common causes of respiratory tract infections and place a burden on health services each winter. Systems to describe the timing and intensity of such activity will improve the public health response and deployment of interventions to these pressures. Here we develop early warning and activity intensity thresholds for monitoring influenza and RSV using two novel data sources: general practitioner out-of-hours consultations (GP OOH) and telehealth calls (NHS 111). Moving Epidemic Method (MEM) thresholds were developed for winter 2017–2018. The NHS 111 cold/flu threshold was breached several weeks in advance of other systems. The NHS 111 RSV epidemic threshold was breached in week 41, in advance of RSV laboratory reporting. Combining the use of MEM thresholds with daily monitoring of NHS 111 and GP OOH syndromic surveillance systems provides the potential to alert to threshold breaches in real-time. An advantage of using thresholds across different health systems is the ability to capture a range of healthcare-seeking behaviour, which may reflect differences in disease severity. This study also provides a quantifiable measure of seasonal RSV activity, which contributes to our understanding of RSV activity in advance of the potential introduction of new RSV vaccines.

Original languageEnglish
Article numbere163
JournalEpidemiology and Infection
Publication statusPublished - 2019

Bibliographical note

Funding Information:
Author ORCIDs. S. E. Harcourt, 0000-0002-2278-9642; G. E. Smith, 0000-0002-4257-0568; R. Pebody, 0000-0002-9069-2885 Acknowledgements. We acknowledge the support from: NHS 111 and NHS Digital for their assistance and support with the NHS 111 system; OOH providers submitting data to the GP OOH system and Advanced. RAM, GES and AJE are supported by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Emergency Preparedness and Response. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health or Public Health England.

Publisher Copyright:
© The Author(s) 2019.


  • Influenza
  • Moving epidemic method
  • Respiratory syncytial virus
  • Syndromic surveillance
  • Thresholds


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