Olfactory Hallucinations Following COVID-19 Vaccination

Abstract

Background: Vaccine-induced phantosmia is a rare adverse effect of vaccination and has not been previously reported related to the Johnson & Johnson (J&J) COVID-19 vaccine. Case Presentation: Three weeks after receiving the J&J COVID-19 vaccine, a 39-year-old veteran started smelling a burning odor in the absence of an identifiable source. At presentation to the clinic, his general and neurological examinations, brain magnetic resonance imaging, and electroencephalogram were all unremarkable. The episodes persisted for nearly 2 years (21 months postvaccination). Conclusions: This is the only case of phantosmia reported after the use of the J&J COVID-19 vaccine and aligns with the literature that reports 1 case of phantosmia and 2 cases of hyposmia following the Pfizer-BioNTech COVID-19 mRNA vaccine. This information will help health care professionals understand the possible adverse effects of COVID-19 vaccination and be better equipped to counsel patients about the benign but potentially long-lasting adverse effects of the J&J COVID-19 vaccine.