Neurologic Disease after Yellow Fever Vaccination, São Paulo, Brazil, 2017–2018

Yellow fever (YF) vaccine can cause neurologic complications. We examined YF vaccine–associated neurologic disease reported from 3 tertiary referral centers in São Paulo, Brazil, during 2017–2018 and compared the performance of criteria established by the Yellow Fever Vaccine Working Group/Centers for Disease Control and Prevention and the Brighton Collaboration. Among 50 patients who met inclusion criteria, 32 had meningoencephalitis (14 with reactive YF IgM in cerebrospinal fluid), 2 died, and 1 may have transmitted infection to an infant through breast milk. Of 7 cases of autoimmune neurologic disease after YF vaccination, 2 were acute disseminated encephalomyelitis, 2 myelitis, and 3 Guillain-Barré syndrome. Neurologic disease can follow fractional vaccine doses, and novel potential vaccine-associated syndromes include autoimmune encephalitis, opsoclonus-myoclonus-ataxia syndrome, optic neuritis, and ataxia. Although the Brighton Collaboration criteria lack direct vaccine causal assessment, they are more inclusive than the Centers for Disease Control and Prevention criteria.