Influenza-related health care utilization and productivity losses during seasons with and without a match between the seasonal and vaccine virus B lineage

Vaccine. 2013 Jul 18;31(33):3370-88. doi: 10.1016/j.vaccine.2013.04.081. Epub 2013 May 23.


Objective: To assess and compare direct medical costs (incurred by payers) and indirect productivity losses (incurred by employers) associated with influenza seasons with matched or mismatched circulating and vaccine containing influenza B lineages.

Methods: A retrospective analysis, using two MarketScan databases, for the years 2000-2009. Each influenza season was categorized as matched or mismatched after comparing that season's circulating influenza B lineage and the vaccine influenza B lineage. Patients selected had at least one diagnosis claim for influenza (ICD-9-CM code 487.xx [influenza] or 488.1 [H1N1]) during an influenza season. We assessed the incidence of influenza (overall and influenza B), influenza-related medical utilization and associated costs, and productivity losses for each season.

Results: The four matched seasons had lower average influenza incidence (overall incidence per 100,000 plan members: 509; 95% confidence interval [CI]: 505-512) than the five mismatched seasons (748; 95% CI: 745-751). The mismatched seasons had lower influenza B incidence (average incidence per 100,000 plan members: 126; 95% CI: 125-128) than the matched seasons (165; 95% CI: 163-167). The average, per-patient, total influenza-related medical costs in the mismatched seasons ($300.83; range: $245.38-$371.58) were approximately $61.00 higher than in the matched seasons ($239.43; range: $201.49-$264.01). The mismatched seasons had greater average per-patient, influenza-related productivity-loss costs than the matched seasons (mean: $237.31 vs. $175.10).

Conclusion: CDC data showed that influenza A was the predominant circulating strain during seasons in which the circulating influenza B lineage did not match the vaccine influenza B lineage. This resulted in lower influenza B incidence during the mismatched seasons. However, the average, per-patient, influenza-related direct medical costs and indirect productivity losses were higher during the mismatched seasons. Additional research is required to determine if these higher costs can be attributed to influenza B infections and if the influenza severity varies during mismatched seasons.

Keywords: CCAE; CDC; CI; Centers for Disease Control and Prevention; Commercial Claims and Encounters; HPM; Health and Productivity Management; Health care cost; ICD-9-CM; International Classification of Diseases, Ninth Revision, Clinical Modification; NREVSS; National Respiratory and Enteric Virus Surveillance System; Productivity loss; Strain mismatch; US; United States; WHO; World Health Organization.; confidence interval.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Cost of Illness*
  • Databases, Factual
  • Female
  • Health Care Costs*
  • Health Services / economics
  • Health Services / statistics & numerical data*
  • Humans
  • Incidence
  • Infant
  • Influenza A Virus, H1N1 Subtype
  • Influenza B virus*
  • Influenza Vaccines / therapeutic use*
  • Influenza, Human / economics*
  • Influenza, Human / epidemiology
  • International Classification of Diseases
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Retrospective Studies
  • Seasons
  • United States / epidemiology
  • Young Adult


  • Influenza Vaccines