Neonatal Herpes Simplex Virus Infection in the United States: Regional and Time Trends, 2017-2021

Neonatal herpes simplex virus (HSV) infection is a relatively rare but devastating disease. Neonatal HSV infection is one of the most serious complications of genital HSV infection but is not reportable in most states and is severely undersurveilled. Estimates of neonatal HSV incidence using up-to-date, nationally representative data are lacking and are needed to inform public health intervention in this area.

We used data from the National Inpatient Sample collected by the Healthcare Cost and Utilization Project to estimate neonatal HSV cases and incidence in the United States from 2017 to 2021. We identified neonatal HSV cases using International Classification of Diseases, Tenth Revision, Clinical Modification codes. We compared cases by region and over time using Wald tests, t tests, and linear regression. We used linear regression with an interaction term to assess whether incidence trends varied by region.

From 2017 to 2021, 1895 neonates had a hospital discharge diagnosis of neonatal HSV for an average of 379 cases per year and a total overall incidence of 10.15 (95% confidence interval [CI], 9.70-10.62) cases per 100,000 live births. Nearly half (47.0%) of identified cases were in the South. From 2017 to 2019, neonatal HSV incidence per 100,000 live births decreased in the Northeast (slope = -1.56; 95% CI, -2.803 to -0.32) and increased in the Midwest (slope = 1.33; 95% CI, 0.09 to 2.57).

Neonatal HSV infection is an ongoing cause of perinatal infection and neonatal hospitalizations. Improved data sources and better surveillance are needed to monitor this disease and to identify areas for intervention.