Impact of varicella vaccination on health care utilization.

CONTEXT Since varicella vaccine was first recommended for routine immunization in the United States in 1995, the incidence of disease has dropped substantially. However, national surveillance data are incomplete, and comprehensive data regarding outpatient as well as hospital utilization have not been reported. OBJECTIVE To examine the impact of the varicella vaccination program on medical visits and associated expenditures. DESIGN, SETTING, AND PATIENTS Retrospective population-based study examining the trends in varicella health care utilization, based on data from the MarketScan databases, which include enrollees (children and adults) of more than 100 health insurance plans of approximately 40 large US employers, from 1994 to 2002. MAIN OUTCOME MEASURES Trends in rates of varicella-related hospitalizations and ambulatory visits and direct medical expenditures for hospitalizations and ambulatory visits, analyzed using 1994 and 1995 as the prevaccination baseline. RESULTS From the prevaccination period to 2002, hospitalizations due to varicella declined by 88% (from 2.3 to 0.3 per 100,000 population) and ambulatory visits declined by 59% (from 215 to 89 per 100,000 population). Hospitalizations and ambulatory visits declined in all age groups, with the greatest declines among infants younger than 1 year. Total estimated direct medical expenditures for varicella hospitalizations and ambulatory visits declined by 74%, from an average of 84.9 million dollars in 1994 and 1995 to 22.1 million dollars in 2002. CONCLUSION Since the introduction of the varicella vaccination program, varicella hospitalizations, ambulatory visits, and their associated expenditures have declined dramatically among all age groups in the United States.