title: What is the utility of using syndromic surveillance systems during large subnational infectious gastrointestinal disease outbreaks? An observational study using case studies from the past 5 years in England.
abstract: Syndromic surveillance systems in England have demonstrated utility in the early identification of seasonal gastrointestinal illness (GI) tracking its spatio-temporal distribution and enabling early public health action. There would be additional public health utility if syndromic surveillance systems could detect or track subnational infectious disease outbreaks. To investigate using syndromic surveillance for this purpose we retrospectively identified eight large GI outbreaks between 2009 and 2014 (four randomly and four purposively sampled). We then examined syndromic surveillance information prospectively collected by the Real-time Syndromic Surveillance team within Public Health England for evidence of possible outbreak-related changes. None of the outbreaks were identified contemporaneously and no alerts were made to relevant public health teams. Retrospectively, two of the outbreaks - which happened at similar times and in proximal geographical locations - demonstrated changes in the local trends of relevant syndromic indicators and exhibited a clustering of statistical alarms, but did not warrant alerting local health protection teams. Our suite of syndromic surveillance systems may be more suited to their original purposes than as means of detecting or monitoring localized, subnational GI outbreaks. This should, however, be considered in the context of this study's limitations; further prospective work is needed to fully explore the use of syndromic surveillance for this purpose. Provided geographical coverage is sufficient, syndromic surveillance systems could be able to provide reassurance of no or minor excess healthcare systems usage during localized GI incidents.
authors.affiliation: Public Health England,Real-time Syndromic Surveillance Team,National Infection Service,Birmingham,UK.
authors.forename: D
authors.initials: D
authors.lastname: Todkill
authors.affiliation: Public Health England,Real-time Syndromic Surveillance Team,National Infection Service,Birmingham,UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Elliot
authors.affiliation: Public Health England,Real-time Syndromic Surveillance Team,National Infection Service,Birmingham,UK.
authors.forename: R
authors.initials: R
authors.lastname: Morbey
authors.affiliation: Public Health England,Gastrointestinal Emerging and Zoonotic Infections,National Infection Service,Colindale,London,UK.
authors.forename: J
authors.initials: J
authors.lastname: Harris
authors.affiliation: Public Health England,Field Epidemiology Service,National Infection Service,Birmingham,UK.
authors.forename: J
authors.initials: J
authors.lastname: Hawker
authors.affiliation: Public Health England,Field Epidemiology Service,National Infection Service,Birmingham,UK.
authors.forename: O
authors.initials: O
authors.lastname: Edeghere
authors.affiliation: Public Health England,Real-time Syndromic Surveillance Team,National Infection Service,Birmingham,UK.
authors.forename: G E
authors.initials: GE
authors.lastname: Smith
mesh_terms: D004196:Disease Outbreaks; D004739:England / Q000453:epidemiology; D005767:Gastrointestinal Diseases / Q000453:epidemiology*; D006801:Humans; D011159:Population Surveillance; D011634:Public Health / Q000379:methods*; D012189:Retrospective Studies
keywords: Gastrointestinal infections; outbreaks; surveillance; surveillance system