Tracking Varicella Deaths: Accuracy and Completeness of Death Certificates and Hospital Discharge Records, New York State, 1989–1995

Before widespread vaccination, varicella infection resulted in more than 11 000 hospitalizations1 and 100 deaths annually in the United States.2 Since vaccine licensure in 1995, varicella incidence has decreased markedly.3 Mathematical models have predicted that vaccination will shift the peak incidence of disease to older ages as the incidence declines.4 Because older persons are at increased risk of morbidity and mortality from varicella,5,6 it is essential to monitor these outcomes as vaccination coverage increases.7,8 The Centers for Disease Control and Prevention (CDC) encourages state health departments to search death certificates and hospital discharge databases to estimate the number of varicella deaths. In this study, we assessed the validity and utility of these data sources.