TOPLINE: 

The incidence of neonatal herpes simplex virus (HSV) infections in the UK and Ireland increased dramatically over 15 years, and outcomes remained poor, with mortality and long-term neurologic morbidity being high despite advances in treatment.

METHODOLOGY:

• This prospective population-based national surveillance study conducted by the British Paediatric Surveillance Unit (BPSU) aimed to determine the incidence of neonatal herpes infections in the UK and Ireland.
• The study included 117 infants younger than 90 days with HSV infection between August 2019 and February 2022.
• Monthly email questionnaires requesting clinical information were sent to all consultants and neonatologists in the UK and Ireland to report all cases of HSV in infants younger than 90 days, with follow-up surveys at 12 and 24 months to assess neurodevelopment, visual impairment, epilepsy, and recurrence.
• HSV infections were classified independently as skin, eye, and mouth infections (32.5%), central nervous system (CNS) infections (35.0%), or disseminated disease (32.5%).

TAKEAWAY:

• The incidence of BPSU-reported neonatal HSV infections increased to 6.0 per 100,000 live births (95% CI, 4.9-7.2) in 2019-2021, whereas laboratory-confirmed data indicate an even higher incidence of 13.7 per 100,000 live births (95% CI, 12.8-14.9).
• The median age at symptom onset was 8 days, with 95.7% of infants showing symptoms before 1 month of age. Fewer than half of the infants with CNS presented with seizures. Among infants with disseminated disease, sepsis was the most frequent presentation (78.9%), followed by jaundice/hepatitis (52.6%) and respiratory distress (50.0%).
• Overall, 23.9% of infants died — 7.3% of those with CNS infections and 65.8% of those with disseminated disease. No deaths were reported among infants with skin, eye, and mouth lesions.
• At the 2-year follow-up, 29.3% of infants had neurodevelopmental impairment, with rates varying by disease type: 11.8% of those with skin, eye, and mouth lesions, 45% with CNS infection, and 25% with disseminated disease.

IN PRACTICE:

"Clinicians should be aware that infants with neonatal herpes are often born to women without a known history of genital herpes and that they can present without a fever, SEM [skin, eye, and mouth] lesions, or elevated infection markers, just with respiratory distress and/or jaundice, most commonly in the first few weeks of life," the authors wrote.

SOURCE:

The study was led by Julia Dudley, Academic Department of Paediatrics, Royal Alexandra Children's Hospital, Brighton, England. It was published online on September 01, 2025, in Archives of Disease in Childhood.

LIMITATIONS:

The BPSU-reported incidence of neonatal HSV infection may have been underestimated due to incomplete case notifications from clinicians, and the laboratory-confirmed incidence may have been overestimated because of inadequate clinical information. Observation and recall bias may have been introduced because clinicians were more likely to remember and follow-up unwell infants.

DISCLOSURES:

The study was funded by the Rocking Horse Charity and the Kit Tarka Foundation. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.