Herpes simplex encephalitis in France: incidence, 6-month rehospitalizations and mortality

Herpes simplex encephalitis (HSE) is a disease with unfavorable vital and functional prognoses. There are no recent epidemiological data on HSE at a national level using real-life databases, especially in France. This study aimed to report the incidence, the clinical characteristics and outcomes of the patients with HSE. We conducted a comprehensive retrospective cohort study on all patients hospitalized for HSE in France between 2015 and 2022 using national hospital discharge databases. Incidence, socio-demographic and clinical characteristics (including comorbidities, seizure, stays’ features, intensive care supports) were described. The short- (first stay) and long-term (6-month) outcomes were reported, in terms of mortality and rehospitalizations. 1425 HSE patients were included (median age 67 [54–77] years old, M/F sex ratio 1.07), giving a mean yearly hospital incidence of 2.3 [2.1–2.5] per 1,000,000 inhabitants. 51.2