Incidence of Neonatal Herpes Simplex Virus Infections in the United States, 2006

OBJECTIVES: Neonatal herpes simplex virus (nHSV) infections, although relatively rare, cause significant morbidity and mortality. Estimates of nHSV incidence across the United States vary widely and have been derived by using a variety of methods. We estimated the incidence of nHSV infections for the United States during 2006, as well as demographic-specific rates, by using nationally and regionally weighted estimates from a population-based sample of inpatient data. METHODS: We examined inpatient records of infants aged 60 days or younger at admission using the Healthcare Cost and Utilization Project Kids' Inpatient Database. Patients with a length of stay that exceeded 7 days (or deceased during hospitalization) were identified at discharge from the International Classification of Diseases, Ninth Revision, Clinical Modification codes for herpes simplex (054.0–054.9). Cases for which patients had been transferred from another hospital or readmitted were excluded from case counts. RESULTS: We found an overall US incidence of 9.6 per 100 000 births in 2006. Rates per 100 000 births among US regions were 8.2 in the Northeast, 12.9 in the Midwest, 8.9 in the South, and 8.8 in the West. Rates of 13.8, 9.9, and 7.5 were observed for black, white, and Hispanic newborns, respectively; these differences were not statistically significant. Rates were significantly higher among cases for which the expected primary payer was Medicaid (15.1) compared with private insurance or managed health care (5.4). Median age at admission was 10 days; 25% of admissions were on the day of birth. CONCLUSIONS: This description of regional and demographic-specific nHSV incidence rates for the United States provides important new information on the extent of this potentially devastating disease.