title: Influenza-related healthcare visits, hospital admissions, and direct medical costs for all children aged 2 to 17 years in a defined Swedish region, monitored for 7 years.
abstract: BACKGROUND
  The seasonal variation of influenza and influenza-like illness (ILI) is well known. However, studies assessing the factual direct costs of ILI for an entire population are rare.
  
  
  METHODS
  In this register study, we analyzed the seasonal variation of ILI-related healthcare visits and hospital admissions for children aged 2 to 17 years, and the resultant parental absence from work, for the period 2005 to 2012. The study population comprised an open cohort of about 78,000 children per year from a defined region. ILI was defined as ICD-10 codes: J00-J06; J09-J15, J20; H65-H67.
  
  
  RESULTS
  Overall, the odds of visiting a primary care center for an ILI was 1.64-times higher during the peak influenza season, compared to the preinfluenza season. The corresponding OR among children aged 2 to 4 years was 1.96. On average, an estimated 20% of all healthcare visits for children aged 2 to 17 years, and 10% of the total healthcare costs, were attributable to seasonal ILI. In primary care, the costs per week and 10,000 person years for ILI varied - by season - from &OV0556;3500 to &OV0556;7400. The total ILI cost per year, including all physical healthcare forms, was &OV0556;400,400 per 10,000 children aged 2 to 17 years. The costs for prescribed and purchased drugs related to ILI symptoms constituted 52% of all medicine costs, and added 5.8% to the direct healthcare costs.The use of temporary parental employment benefits for caring of ill child followed the seasonal pattern of ILI (r = 0.91, P < 0.001). Parental absence from work was estimated to generate indirect costs, through loss of productivity of 5.2 to 6.2 times the direct costs.
  
  
  CONCLUSIONS
  Direct healthcare costs increased significantly during the influenza season for children aged 2 to 17 years, both in primary and hospital outpatient care, but not in hospital inpatient care. Primary care manages the majority of visits for influenza and ILI. Children 2 to 4 years have a larger portion of their total healthcare encounters related to ILI compared with older children. There is a clear correlation between ILI visits across the years and parental absence from work.
authors.affiliation: Department of Medical and Health Sciences, Division of Healthcare Analysis Department of Medical and Health Sciences, Division of Community Medicine/General Practice, Linköping University, Linköping, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Rahmqvist
authors.forename: Kristian
authors.initials: K
authors.lastname: Gjessing
authors.forename: Tomas
authors.initials: T
authors.lastname: Faresjö
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003695:Delivery of Health Care / Q000191:economics / Q000706:statistics & numerical data*; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data*; D006801:Humans; D007251:Influenza, Human / Q000191:economics* / Q000628:therapy; D012621:Seasons; D013548:Sweden / Q000453:epidemiology