title: Impact of hepatitis A vaccination on health care utilization in the United States, 1996-2004.
abstract: BACKGROUND
  Since 1996, hepatitis A vaccine has been recommended for persons at risk for infection and children living in communities with the highest disease rates. In 1999, this recommendation was expanded to include all children in 17 states with high incidence compared to a national baseline period. Reported hepatitis A incidence has decreased substantially since 1999; however, comprehensive data on changes in hospital and outpatient utilization have not been reported.
  
  
  OBJECTIVE
  To analyze a health insurance claims database to examine impacts of the hepatitis A vaccination program on medical visits and associated expenditures.
  
  
  METHODS
  We conducted a retrospective study of the 1996-2004 Medstat MarketScan databases, which include enrollees of more than 100 health insurance plans offered by approximately 40 large employers each year, using 1996 and 1997 as the pre-vaccination baseline. Trends in rates of medical care visits were analyzed using Poisson regression method.
  
  
  RESULTS
  From the pre-vaccination era to 2004, hospitalizations due to hepatitis A declined by 68.5% (from 0.81 to 0.26 per 100,000 population, P<0.001) and ambulatory visits declined by 41.5% (from 12.9 to 7.5 per 100,000 population, P<0.001). Ambulatory visits declined in all age groups, with the greatest declines among children<18 years old. Declines were greater among enrollees who resided in the 17 vaccinating states (58.5%) than those in non-vaccinating states (32.7%, P<0.001). After adjusting to the US population, using data derived from a privately insured population, total estimated direct medical expenditures for hepatitis A-related hospitalizations and ambulatory visits declined by 68.1%, from an average of $29.1 million in 1996 and 1997 to $9.3 million in 2004.
  
  
  CONCLUSIONS
  Since the introduction of the hepatitis A vaccination program, hospitalizations, ambulatory visits, and their associated expenditures due to hepatitis A disease have declined substantially among all age groups across the US. Greater declines were seen in the 17 states with vaccination recommendations for hepatitis A.
authors.affiliation: National Center for Immunization and Respiratory Diseases (NCIRD), Centers for Disease Control and Prevention (CDC), Atlanta, GA 30333, United States. faz1@cdc.gov
authors.forename: Fangjun
authors.initials: F
authors.lastname: Zhou
authors.forename: Abigail
authors.initials: A
authors.lastname: Shefer
authors.forename: Cindy
authors.initials: C
authors.lastname: Weinbaum
authors.forename: Mary
authors.initials: M
authors.lastname: McCauley
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D005260:Female; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006296:Health Services / Q000191:economics / Q000706:statistics & numerical data*; D006506:Hepatitis A / Q000517:prevention & control* / Q000821:virology; D022362:Hepatitis A Vaccines / Q000008:administration & dosage*; D030041:Hepatitis A virus / Q000276:immunology; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007231:Infant, Newborn; D007348:Insurance, Health; D008297:Male; D008875:Middle Aged; D009819:Office Visits / Q000191:economics / Q000706:statistics & numerical data; D015397:Program Evaluation; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D022362:Hepatitis A Vaccines