No Cognitive Benefit from Prolonged Antiviral Therapy in Herpes Simplex Encephalitis

Acyclovir has vastly improved the prognosis of herpes simplex encephalitis (HSE), lowering HSE-related mortality from 70% to ≤30%. Still, neurological impairment is common among survivors. Researchers hypothesized that prolonged antiviral treatment might prevent ongoing brain inflammation and improve long-term neurological outcomes. In a double-blind multinational trial, 87 adults with HSE who had received usual 2- to 3-week courses of high-dose intravenous acyclovir were randomized to either oral valacyclovir (2 g thrice daily) or placebo for 90 additional days.

At baseline and at all subsequent evaluations during 24 months of follow-up, the valacyclovir group was indistinguishable neurologically from the placebo group, as assessed on stand…