Neonatal herpes simplex virus (nHSV) infection is rare but can cause serious morbidity and mortality. This study assessed the incidence, mortality, and costs of nHSV infections in the United States in 2019.

Inpatient records of neonates aged 28 days or less at admission were examined using the 2019 Healthcare Cost and Utilization Project Kids' Inpatient Database, a nationally representative sample of U.S. pediatric discharges. Neonatal herpes simplex virus cases were defined as those with ICD-10-CM codes for herpes simplex virus (B00.xx, A60.xx, or P35.2), and hospital stays greater than 5 days or resulting in death. Cases involving readmission or transfer from another hospital were excluded. Incidence, mortality, and costs were estimated by sociodemographic factors including race, U.S. region, primary payer, and median household income.

In 2019, there were an estimated 561 nHSV cases in the United States (15.7 per 100,000 births), with a 4.6% mortality rate. Incidence rates were highest in neonates of Black race (27.3), in the South (21.3), with public insurance coverage (25.2), and born into a household with a median income less than $48,000 (24.5). The incidence rate of nHSV in preterm (41.8) was three times that of term neonates (13.0). The median hospital stay was 15 days with a median cost of $109,562.

We found disparities in nHSV incidence, with infants in the South and born to Black birthing parents disproportionately affected. Higher incidence rates were also found in infants with public insurance coverage and lower household income. Prevention efforts and early detection are crucial to mitigate these disparities.