Herpes simplex virus type 2 encephalitis in critically ill adults: A retrospective analysis of EURECA and Herpetics cohort studies
Herpes simplex virus type 1 (HSV-1) is the leading cause of sporadic infectious encephalitis. Although typically associated with benign meningitis, HSV-2 can also cause encephalitis in adults, a condition that remains poorly characterized in intensive care unit (ICU). We aimed to compare the characteristics, management, and outcomes of critically ill adult with HSV-2 and HSV-1 encephalitis. We performed a retrospective analysis of adults with herpes simplex encephalitis (HSE) admitted to the ICU in two large multicenter cohorts. Patients were classified according to cerebrospinal fluid (CSF) HSV genotype. The primary endpoint was unfavourable outcome at 3 months, defined as a modified Rankin Scale score 3–6. Among 285 HSE patients, 17 (6%) had HSV-2 encephalitis (age 60 [53–67] years, female sex 58.8%). Although the proportion of immunocompromised status did not differ significantly between groups (29.4% vs 15.4%, p = 0.13), HSV-2 cases had a significantly higher prevalence of HIV infection (17.6 vs 1.5%, p < 0.01), less frequent brain MRI abnormalities (85.7% vs 97.7%, p = 0.01) and similar CSF findings compared to HSV-1 cases. The duration of intravenous acyclovir treatment was shorter for HSV-2 cases (18 [4–21] days) versus 21[20–21] days, p = 0.04). Unfavourable outcome occurred in 9/16 (56.3%) patients with HSV-2 encephalitis and in 175/236 (74.2%) patients with HSV-1 encephalitis (p = 0.25). Encephalitis caused by HSV-2 represent a consistent proportion of severe HSE. Clinical presentation and outcomes and broadly comparable to those of HSV-1 cases, underscoring the importance of early recognition and standardized management of encephalitis caused by HSV, regardless of genotype.
Authors
- Omar Ben Hadj Salem (ORCID: https://orcid.org/0000-0001-7639-3291)
- Janneke Horn (ORCID: https://orcid.org/0000-0002-3788-7675)
- Charline Sazio
- Sophie Demeret (ORCID: https://orcid.org/0000-0002-0523-6472)
- Pierre Jaquet (ORCID: https://orcid.org/0000-0003-0922-3393)
- Russell Chabanne (ORCID: https://orcid.org/0000-0001-8953-3716)
- J.C Lachérade
- Nolan Hassold (ORCID: https://orcid.org/0000-0003-0944-4997)
- Ahmed El Kalioubie
- Aurélien Frerou (ORCID: https://orcid.org/0000-0001-8478-1753)
- Pierre Bailly (ORCID: https://orcid.org/0000-0001-8187-8672)
- Giuseppe Citerio (ORCID: https://orcid.org/0000-0002-5374-3161)
- Étienne de Montmollin (ORCID: https://orcid.org/0000-0001-6379-1928)
- Nicolas Engrand (ORCID: https://orcid.org/0000-0002-6051-5474)
- Jean-Marc Tadié
- Fabrice Bruneel (ORCID: https://orcid.org/0000-0003-4772-6602)
- Benjamine Sarton
- Dr M.K. Renuka
- Noelle Brule
- D. Daubin
- A. Massri
- A. Robert
- E. . Mariotte
- M. . Landais
- C. . Schwebel
- C. Brault
- EURECA study groups
- N. Engrand
- T. . Ritzenthaler
- G. . Louis
- G. . Voiriot
- A. . Marchalot
- A. . Radjou
- B. . Souweine
- A. Joret
- V. Susset
- F. . Chemouni
- A. Stoclin
- D. . Contou
- M. . Santafe
- M. Conrad
- M. Pilar Martin
- P. . Chillet
- Mikael Alves
- P. Trouiller
- G. . De Pascale
- Daniel E. da Silva
- K. . Klouche
- J. . Audibert
- P. . Mateu
- K. . Razazi
- B. . Sztrympf
- Bertrand Guidet
- B. Mourvillier
- G. . Papin
- Romain Sonneville
- Claire Dupuis
- M. Wolff
- S. Gaudry
- the ENCEPHALITICA
- G. . Geri
- E. . Val Jordan
- A. . Cariou
- C. . Bruel
- T. . Duburcq
- S. . Bedanta Mishra
- D. . Schnell
- P. . Vera
- N. Lerolle
- H. . Georges
- D. . Reuter
- R. . Larcher
- L. . Argaud
- P. Bailly
- E. . Escudier
- L. Bouadma
- A. Berger
- J.P. Quenot
- M. . Thyrault
- R. . Smonig
- F. Mateos
- J.P. Mira
- P. . Boronat
- R. . Chabanne
- R. . Ferrer
- Jean-François Timsit
- C. Ragot
- A. Lautrette
- S. . Saxena
- B. . Balandin Moreno
- J. . Bourenne
- F. . Bruneel
- D. . Roux
- F. Dailler
- F. . Barbier
- M. Murgier
- M. Schmidt
- B. Guidet
- E. Novy
- C. Sazio
- S. . Hraiech
- Mo . Gurjar
- Thomas Volpé
- V. Das
- N. . Aissaoui
- M. . Kofler
- L. . Le Guennec
- S. Silva
- I. . Calamai
- A. Levrat
- S. . Siami
- Q. Maestraggi
- I. . Martin-Loeches
- Raimund Helbok
- J. Marechal
Institutions
- Université Claude Bernard Lyon 1 (FR)
- Johannes Kepler University of Linz (AT)
- Université de Bordeaux (FR)
- Inserm (FR)
- Délégation Paris 7 (FR)
- Université Paris Cité (FR)
- Centre Hospitalier Universitaire de Nantes (FR)
- Sorbonne Université (FR)
- Sorbonne Paris Cité (FR)
- Assistance Publique – Hôpitaux de Paris (FR)
- Hôpital Roger Salengro (FR)
- Hôpital Saint-Antoine (FR)
- Bordeaux Population Health (FR)
- Centre Hospitalier Intercommunal de Poissy (FR)
- Kepler Universitätsklinikum (AT)
- Pitié-Salpêtrière Hospital (FR)
- Hôpital Pontchaillou (FR)
- Fondation de Rothschild (FR)
- Laboratoire de Recherche Vasculaire Translationnelle (FR)
- Hôpital Purpan (FR)
- Hôpital Bichat-Claude-Bernard (FR)
- Centre Hospitalier Saint-Denis (FR)
- Amsterdam University Medical Centers (NL)
- Centre Hospitalier de Versailles (FR)
- Hôpital Maison Blanche (FR)
- University of Milano-Bicocca (IT)
- Nantes Université (FR)
Publication Details
- Journal
- Critical Care
- Published
- 2026-03-13
- DOI
- https://doi.org/10.1186/s13054-026-05865-6
- Primary Topic
- Herpesvirus Infections and Treatments
- Type
- article
- Field-Weighted Citation Impact
- 0.00