Though autoimmune cerebellar ataxia is more common in mGluR1 encephalitis (10), a 29-year-old man with bilateral horizontal nystagmus, ataxia after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, was reported with mGluR5 antibodies in the cerebrospinal fluid and serum, with abnormal signals in the splenium of the corpus callosum rather than cerebellum (7). This evidence concerns the gene GRM5 and viral encephalitis.