Impact of hepatitis A vaccination on health care utilization in the United States, 1996-2004

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.