ObjectivesNeonatal herpes simplex virus (HSV) infection is a rare but dangerous condition. Previous national British Paediatric Surveillance Unit (BPSU) studies¹,² showed a doubling of incidence of neonatal HSV from 1.65 to 3.6/100,000 between 1991–2006. More recent data are required to inform future practice around prevention and treatment. This BPSU study aimed to define the: (1) current incidence of HSV disease and virus types in UK and Irish infants over a 2.5 year period, (2) types of HSV disease, (3) presentations and management, (4) source of transmission, (5) antenatal risk factors.MethodsProspective surveillance of HSV infection in infants < 90 days of age in UK and Ireland occurred between July 2019 and February 2022 via the BPSU. Paediatricians reporting cases were requested to complete a detailed questionnaire. Semi-anonymised patient identifiers allowed removal of duplicate cases. Collection of one and two-year follow-up data is ongoing.Results242 cases were reported to BPSU, 25 were errors. 179 questionnaires were returned, 61 duplications were removed leaving 118 cases for analysis. Estimated incidence is 6.9 cases per 100 000 live births. 39/114 (34%) were born <37 weeks gestation. 39/118 (33%) had disseminated disease, 35% CNS and 32% skin/eye/mouth (SEM) infection. Median day of onset was 6 for disseminated, 8 for SEM and 14 for CNS infections. 61% with disseminated and CNS disease had HSV2 infections and 76% with SEM disease had HSV1. of those with disseminated disease, 18% had a fever and 26% had SEM lesions at presentation. Aciclovir was commenced in 113/118 but in only 40/118 (34%) on the day of presentation. Overall mortality was 24% but was related to disease type (66% with disseminated disease died compared to 7% of those with CNS infection), gestation (57% <28 weeks died compared to 19% >37 weeks) and admission and peak ALT. (Fig 1 compares admission and peak ALT in surviving infants and those who died).ConclusionUK incidence of neonatal HSV has doubled since the last national surveillance study and mortality remains high. Outcomes are particularly poor in premature infants. Early detection of disseminated disease is challenging as presenting features are non-specific, meaning treatment is commonly delayed. Raising awareness and national guidance on the management of this infection is required. Follow-up focusing on disease recurrence and morbidity at 12 and 24 months is ongoing.ReferencesTookey PA, Peckham CS. Neonatal herpes simplex virus infection in the British Isles. Paediatr Perinat Epidemiol 1996 Oct;10(4):432–42.Tookey PA, Mahdavi S, Peckham CS. Surveillance of neonatal herpes in the British Isles 2004–2006 [version 1; peer review: 1 approved with reservations, 1 not approved]. F1000Research 2020, 9:163 (https://doi.org/10.12688/f1000research.21538.1)Abstract 912 Figure 1...

912 Herpes simplex virus in infants under 90 days of age in UK and Ireland: results of the 2019–2022 BPSU study

10.1136/archdischild-2023-rcpch.291