title: Detection of varying influenza circulation within England in 2012/13: informing antiviral prescription and public health response.
abstract: BACKGROUND
  Subnational variation of 2009 pandemic influenza activity in England has been reported; however, little work has been published on this topic for seasonal influenza. If variation is present, this knowledge may assist with both identifying the onset of influenza epidemics, informing community antiviral prescription and local health planning.
  
  
  METHODS
  An end-of-season analysis of influenza surveillance systems (acute respiratory outbreaks, primary care consultations, virological testing, influenza-confirmed secondary care admissions and excess all-cause mortality) was undertaken at national and subnational levels for 2012/13 when influenza B and A(H3N2) dominated.
  
  
  RESULTS
  National community antiviral prescription was recommended in Week 51 following national threshold exceedance. However, this was preceded up to 2 weeks by subnational influenza activity in 2/9 regions in England. Regional variation in circulation of influenza subtypes was observed and severe influenza surveillance data sources were able to monitor the subnational impact.
  
  
  CONCLUSIONS
  Evidence of virological activity in two or more regions above a threshold indicated the onset of the 2012/13 season. Subnational thresholds should be determined and evaluated in order to improve timeliness of the national antiviral alert. During the season, outputs should be reported at levels that can inform local public health responses and variation considered when retrospectively evaluating the impact of interventions.
authors.affiliation: Respiratory Diseases Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London NW9 5EQ, UK.
authors.forename: H K
authors.initials: HK
authors.lastname: Green
authors.affiliation: Respiratory Diseases Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London NW9 5EQ, UK.
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Respiratory Diseases Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London NW9 5EQ, UK.
authors.forename: N L
authors.initials: NL
authors.lastname: Boddington
authors.affiliation: Statistics Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London NW9 5EQ, UK.
authors.forename: N
authors.initials: N
authors.lastname: Andrews
authors.affiliation: Royal College of General Practitioners Research and Surveillance Centre, Birmingham B17 9DB, UK.
authors.forename: H
authors.initials: H
authors.lastname: Durnall
authors.affiliation: Real Time Syndromic Surveillance Team, Public Health England, Birmingham B3 2PW, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Elliot
authors.affiliation: Real Time Syndromic Surveillance Team, Public Health England, Birmingham B3 2PW, UK.
authors.forename: G
authors.initials: G
authors.lastname: Smith
authors.affiliation: Field Epidemiology Services North East, Public Health England, Newcastle upon Tyne NE1 4WH, UK.
authors.forename: R
authors.initials: R
authors.lastname: Gorton
authors.affiliation: Bristol Public Health Laboratory, Public Health England, Bristol BS2 8EL, UK.
authors.forename: M
authors.initials: M
authors.lastname: Donati
authors.affiliation: Public Health England Respiratory Virus Unit, Virus Reference Department, Reference Microbiology Services, PHE Colindale, London NW9 5EQ, UK.
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.affiliation: Public Health England Respiratory Virus Unit, Virus Reference Department, Reference Microbiology Services, PHE Colindale, London NW9 5EQ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Zambon
authors.affiliation: Respiratory Diseases Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London NW9 5EQ, UK.
authors.forename: R
authors.initials: R
authors.lastname: Pebody
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use*; D004196:Disease Outbreaks; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D011159:Population Surveillance; D011634:Public Health
chemical_list: D000998:Antiviral Agents
keywords: England; epidemiology; influenza; morbidity and mortality; respiratory disorders; surveillance