1155. US Healthcare Costs for Illness Attributable to Seasonal Influenza Type A and Type B During 2001/2002 2008/2009
Session: Poster Abstract Session: Public Health
Friday, October 9, 2015
Room: Poster Hall
Background: While the overall healthcare burden of seasonal influenza in the US has been well documented, the proportion of influenza burden attributable to type A and type B illness warrants further research.

Objective: To estimate the numbers of healthcare encounters and healthcare costs attributable to influenza viral strains A and B in the US during the 2001/2002 – 2008/2009 seasons.

Methods: An Excel model was developed to estimate healthcare encounters and costs in the US during the 2001/2002 – 2008/2009 seasons for influenza type A and type B separately and collectively, by season, care setting, and age group. Rates of influenza-related encounters requiring formal healthcare, unit costs of influenza-related healthcare encounters, and estimates of population size were based on data from published literature, data on file, and secondary sources (GSK ID: HO-13-12299). 

Results:  The projected annual number of influenza-related healthcare encounters ranged from 11.3 million (2008/2009) to 25.6 million (2007/2008), with a mean of 17.3 million. Overall healthcare costs ranged from $2.0 billion (2008/2009) to $5.8 billion (2007/2008); mean cost was $3.5 billion. Outpatient visits accounted for 99% of all encounters, and almost two-thirds of healthcare costs.  While the majority of disease was attributable to type A, type B influenza accounted for 4.2% (2003/2004) to 63.8% (2002/2003) of all influenza-related healthcare encounters, and 2.8% (2003/2004) to 66.0% (2002/2003) of influenza-related healthcare costs; corresponding mean percentages over all seasons was 40.8% and 37.0%, respectively.  The percentage of influenza-related healthcare encounters attributable to type B infection was higher in the outpatient setting (40.9%) than in the inpatient setting (27.8%).

Conclusion: Influenza was associated with substantial clinical and economic burden. Although the fraction of this burden attributable to type B disease varied substantially across years, it was, on average, responsible for 37% of total influenza-related healthcare costs. Increasing influenza vaccine coverage, especially with the recently approved quadrivalent products that include an extra type B strain, may significantly reduce the overall annual burden of influenza in the US.

Songkai Yan, M.S.1, Derek Weycker, Ph.D.2, Stephania Sokolowski, B.A.2 and Girishanthy Krishnarajah, Ph.D.3, (1)US Health Outcomes & Epidemiology, GlaxoSmithKline: USHO & Epi - Vaccines, Philadelphia, PA, (2)Policy Analysis Inc. (PAI), Brookline, MA, (3)US Health Outcomes & Epidemiology - Vaccines USMA Health Outcomes, GlaxoSmithKline: USHO Vaccines, Philadelphia, PA


S. Yan, GlaxoSmithKline Biologicals SA: Research Contractor , Research support

D. Weycker, GlaxoSmithKline Biologicals SA: Research Contractor , Research support

S. Sokolowski, GlaxoSmithKline Biologicals SA: Research Contractor , Research support

G. Krishnarajah, GlaxoSmithKline: Employee , Research support

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