Encephalitis has an annual incidence of 2-3 per 100,000, with 40% being infectious, 40% of unknown cause, and 20% immune-mediated. Anti-NMDA receptor encephalitis and VGK Complex antibody-positive encephalitis are major immune-mediated categories. It is more common in women and younger patients.

Encephalitis due to any cause has a yearly incidence of 2–3 per 100,000 in northern Europe, which is half the incidence of multiple sclerosis (4–8 per 100,000 annually).

• While 40% of cases are infectious and 40% are attributable to unknown causes, at least 20% are immune-mediated, with anti-NMDA-receptor encephalitis (4%) and VGK Complex antibody-positive encephalitis (3%) constituting the major categories.

• The condition is more prevalent among women (81%) and younger patients (37% 18 years, 95% 45 years); however, in the age categories younger than 12 years and older than 45 years, the disease is more prevalent among men nearly half of patients are male.

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