Surveillance of neonatal herpes in the British Isles 2004-2006

Abstract

Background: Neonatal herpes simplex virus (HSV) infection is rare but potentially devastating and can result in neonatal death or serious disability. National incidence was estimated at 1.65/100,000 live births in an earlier British Paediatric Surveillance Unit (BPSU) study of births 1986-1991. Methods: A second surveillance study of neonatal HSV was undertaken through the BPSU 2004-2006, with follow-up information collected on surviving children in early childhood. Results: Over the three-year period, 85 infants were reported with confirmed neonatal HSV, an estimated incidence of 3.58/100,000 live births (95% CI 2.86-4.42), about double that reported almost two decades earlier. Over 40% of infants were pre-term compared with 25% in the earlier period. Just over 70% had central nervous system (CNS) or disseminated infection, and among these 54% had no skin, eye or mouth lesions noted. Almost all received antivirals, but 22 (26%) neonates died, all with disseminated or CNS infection. All but six infections were typed, of which 57% involved HSV-2; the increased risk of adverse outcomes associated with HSV-2 in the earlier study was confirmed and strengthened, with twice as many deaths or long term disability in infants with HSV-2 than HSV-1. As before, a reported history or diagnosis of maternal HSV infection was rare prior to infant diagnosis. Likely timing of infant exposure to HSV could only be assigned in 43% of cases, of which just over half were probable postnatal transmissions. Conclusions: Neonatal HSV infection remains rare although incidence doubled in the British Isles between the late 1990s and the mid-2000s. These findings suggest that future research should explore the relationship between pre-term delivery and infant susceptibility, and also the role of postnatal acquisition of infection. Healthcare professionals and new parents must continue to be aware of this rare condition in order to enable prompt investigation and instigation of treatment.