Deniz, CigdemAltunan, BenguUnal, Aysun2024-10-292024-10-2920231300-06671309-4866https://doi.org/10.29399/npa.28251https://search.trdizin.gov.tr/tr/yayin/detay/1228589https://hdl.handle.net/20.500.11776/14630Since December 2020, a significantly higher number of people worldwide have been vaccinated for coronavirus disease 2019 (COVID-19). Neurological complications have been reported after these vaccines, although a definitive causal relationship has not been proven in the available literature. We describe a 51-year-old man presenting with anti-glutamic acid decarboxylase (anti-GAD) antibody positive autoimmune encephalitis with progressive cognitive impairment and behavioral abnormalities, presenting shortly after the second dose of mRNA COVID-19 vaccine, possibly representing a serious vaccine related adverse event. Response to high-dose steroid and intravenous immunoglobulin treatment was positive. As many people around the world have been vaccinated against COVID-19, this case shows that autoimmune encephalitis and even anti-GAD antibody positive autoimmune encephalitis can develop as a side effect after this new vaccine, but with early diagnosis and appropriate treatment, the clinic can have a good prognosis. Observational studies with large numbers of patients are needed to explain causality.en10.29399/npa.28251info:eu-repo/semantics/openAccessanti-GAD encephalitisautoimmune encephalitisCOVID-19 vaccinationArticle603283287Q4WOS:0010556201000142-s2.0-85168563981122858937645084Q3