Page 107 - ITPS-8-3

INNOSC Theranostics

and Pharmacological Sciences

CASE SERIES
Persistent smell and taste disorders following

COVID-19 vaccination: A report of three cases
and review of the literature

Sherifa Ahmed Hamed * , Ahmed Elrahman Mohamed Azzam Abdel-Razek
1
Ahmed 2 , and Mohamed Azzam Abdel-Razek Ahmed 2
1 Department of Neurology and Psychiatry, Assiut University Hospital, Assiut, Egypt
2 Department of Ear, Nose and Throat, Assiut University Hospital, Assiut, Egypt

Abstract

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
*Corresponding author:
Sherifa Ahmad Hamed 2024 with persistent hyposmia for 3 years. These persistent disorders may be due
(hamedsherifa@aun.edu.eg) to immune responses triggered by the vaccine, potentially affecting the olfactory
Citation: Hamed SA, neuroepithelium. Recognition and reporting of such adverse effects are important to
Ahmed AEMAA, and Ahmed MAA. acknowledge among physicians and for future studies and treatment trials targeting
Persistent smell and taste disorders related disorders.
following COVID-19 vaccination: A
report of three cases and review of
the literature. INNOSC Theranostics
and Pharmacological Sciences. Keywords: COVID-19 vaccine; Anosmia; Ageusia; Parosmia; Dysgeusia
2025;8(3):101-106.
doi: 10.36922/ITPS025140020
Received: April 03, 2025 1. Introduction
Revised: May 29, 2025
Several vaccines were rapidly developed and approved to combat COVID-19 in the early
Accepted: May 30, 2025
stages of the pandemic. The common and worldwide distributed vaccines included Pfizer-
Published online: June 17, 2025 BioNTech, Moderna, AstraZeneca/Oxford, and Johnson and Johnson (J and J or Janssen).
Copyright: © 2025 Author(s). The Pfizer-BioNTech and Moderna vaccines are messenger RNA (mRNA) delivered to host
This is an Open-Access article cells to express the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike
distributed under the terms of the
Creative Commons Attribution protein, which is used by the virus to gain entry into host cells. In contrast, the AstraZeneca/
License, permitting distribution, Oxford and Janssen vaccines are viral vectors encoding the SARS-CoV-2 spike protein.
and reproduction in any medium, The expression or delivery of spike protein into the host cells by the vaccines will elicit
provided the original work is
properly cited. an immune response, production of antibodies against the spike protein, activation of
T-cells, and generation of memory cells to combat future SARS-CoV-2 infection, thereby
Publisher’s Note: AccScience
Publishing remains neutral with preventing viral manifestations or decreasing their severity and duration.
regard to jurisdictional claims in
published maps and institutional Several studies have documented the significant contribution of COVID-19 vaccines
1
affiliations. in the reduction of morbidity and mortality. However, as with other vaccines, adverse

Volume 8 Issue 3 (2025) 101 doi: 10.36922/ITPS025140020