Since 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 vaccinerelated
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.
Keywords: anti-GAD encephalitis, autoimmune encephalitis, COVID-19
vaccination