OBJECTIVE: Herpetic meningoencephalitis is characterized by a severe prognosis. Neurological involvement is secondary to recurrence in adults. We report the first case of meningoencephalitis caused by the herpes simplex virus 1 (HSV-1) which occurred immediately after vaccination against the coronavirus disease 2019 (COVID-19).

CASE PRESENTATION: A 42-year-old woman with no previous medical history received her first dose of the SARS-CoV-2 vaccine [heterologous rAd26 and rAd5 vector-based SARS-CoV-2 vaccine (Sputnik®)] while asymptomatic. Two weeks later, the patient presented with asthenia and obnubilation requiring hospitalization in the Intensive Care Unit of the Infectious Diseases Department (Hedi Chaker Hospital, Sfax, Tunisia). Magnetic resonance brain imaging showed an abnormal signal from the inner side of the right temporal lobe in T1 iso-signal and T2 hyper-signal. The patient tested positive for HSV-1; thus, the diagnosis of herpetic meningoencephalitis was retained. The patient’s general condition and her laboratory test results improved after receiving treatment with acyclovir. The treatment was maintained for 14 days and the patient was discharged from the hospital without any central nervous system impairment.

CONCLUSIONS: The recurrence of HSV-1 infection following SARS-CoV-2 vaccine is exceptional. We report the first possible link between SARS-CoV-2 vaccination and the recurrence of herpetic meningoencephalitis.