Persistent smell and taste disorders following COVID-19 vaccination: A report of three cases and review of the literature

Persistent smell and taste disorders following COVID-19 vaccination are rare adverse effects. Herein, we reported three cases in which patients developed smell and taste disorders 9 – 20 days after receiving their second dose of the AstraZeneca/Oxford COVID-19 vaccine in 2021. These symptoms persisted for 1 – 3 years. All patients underwent nasal endoscopy, imaging of the nasal and olfactory structures, as well as Sniffin’ Odor along with flavor and taste identification tests. Case 1 was a 37-year-old male who presented in December 2022 with persistent dysgeusia for 18 months. Case 2 was a 40-year-old male who presented in February 2023 with persistent anosmia and parosmia for 20 months. Case 3 was a 48-year-old male who presented in August 2024 with persistent hyposmia for 3 years. These persistent disorders may be due to immune responses triggered by the vaccine, potentially affecting the olfactory neuroepithelium. Recognition and reporting of such adverse effects are important to acknowledge among physicians and for future studies and treatment trials targeting related disorders.