KEYWORDS:
varicella, chickenpox, zoster, shingles, vaccine

BACKGROUND:
The varicella vaccine was licensed for use in the U.S. in 1995. Neither varicella nor zoster are currently reportable to the Minnesota Department of Health; therefore, information is limited on vaccine uptake and the incidence of varicella and zoster in Minnesota.

OBJECTIVE:
To determine how the rate of hospital visits due to varicella and zoster has changed since 1995.

METHOD:
Data used in this study are a part of the Minnesota Hospital Discharge Database and include discharges of all hospitalizations occurring at participating hospitals over a six-year period. Over 9.5 million discharge records were queried for varicella and zoster ICD-9 codes, stratified by gender, age, and geographic region. Records were analyzed for hospitalization rates, complications, medical procedures, charge, and length of stay.

RESULT:
Preliminary: Varicella hospitalizations dropped markedly following vaccine licensure. Adults over 40 incurred greater costs and were more likely to be hospitalized longer for varicella and zoster than were young children. The rates of hospital visits for varicella and zoster varied across several public health districts in Minnesota.

CONCLUSION:
In the absence of true disease incidence data, this study has provided quantitative indicators of severe disease incidence and estimates of costs incurred by the health care system. Many complications, avoidable hospital visits, and associated costs due to varicella could be reduced with improved vaccine uptake. The use of hospital discharge data to evaluate a condition frequently treated in the home is a notable limitation of the study.

LEARNING OBJECTIVES:
Describe how the rate of hospital visits due to varicella and zoster has changed since 1995, and the programmatic implications of these data.