Page 108 - ITPS-8-3

INNOSC Theranostics and
Pharmacological Sciences Persistent olfactory and gustatory dysfunctions caused by COVID-19 vaccination

effects have been reported. Common adverse effects Sniffin’ Odor’ identification test (SOIT), taste, and flavor
such as fever, fatigue, muscle soreness, malaise, chills, identification tests, as previously described. 12,13
arthritis, and headache occur more frequently than the
otolaryngological ear, nose, and throat (ENT) effects, 2. Case presentation
which include anosmia/hyposmia, ageusia/hypogeusia, 2.1. Case 1
parosmia, phantosmia, and dysgeusia. According to the
COVID‐19 vaccine analysis report released in the UK, there A 37-year-old male developed anosmia and ageusia 9 –
were 70 cases of anosmia, 58 parosmia, and six hyposmia 10 days after receiving the second dose of the AstraZeneca/
out of the 100,809 recipients of the Pfizer-BioNTech Oxford vaccine (June 2021, administered in Egypt). No
vaccine; 802 cases of anosmia, parosmia, and hyposmia systemic manifestations were reported after vaccination.
2
among 25 million recipients of the AstraZeneca/Oxford After 3 months, parosmia and dysgeusia (described
vaccine; and 402 cases of parosmia were recorded among as smoked or burned-out smell and taste) developed
842,270 recipients of the AstraZeneca vaccine. Studies and resulted in weight loss, depression, and insomnia.
3
have suggested a higher incidence of ENT adverse effects Improvement in smell and taste were reported several
with mRNA vaccines compared to viral vector vaccines months after onset, along with resolution of parosmia.
(78.3% vs. 70.4%, p=0.064), while systemic adverse effects Past medical history included a confirmed COVID-19
were more common with viral vector vaccines (87.2% vs. infection in May 2020, verified by a positive PCR test for
4
61%, p=0.001). Some studies reported a higher frequency SARS-CoV-2. Viral manifestations included fever, fatigue,
of ENT adverse effects with the Oxford-Pfizer-BioNTech cough, expectoration, and loss of smell and taste, all of
(BNT162b2) vaccine than with the Moderna COVID-19 which resolved completely within 30 days. Presentation in
vaccine (mRNA-1273) (Ageusia: 0.755% versus 0.608%, December 2022 was due to persistent severe dysgeusia for
p=0.001; Dysgeusia: 0.681% versus 0.486, p=0.001). 18 months. Sniffin’odor, flavor, and taste identification tests
5
Most of these reports estimated that the time elapsed revealed intact smell, flavor, and taste sensations.
from administration of the COVID-19 vaccine to the
development of smell and taste disorders ranged from 1 to 2.2. Case 2
20 days (mainly 1 – 9 days). They also reported favorable A 40-year-old male developed anosmia 20 days after
outcomes with complete resolution of manifestations receiving the second dose of the AstraZeneca/Oxford
4,5
within 4 – 8 weeks. However, to date, there are six vaccine (June 2021, administered in Saudi Arabia).
published case reports of long-term or persistent smell and Parosmia (described as a rotten odor) developed 4 months
taste disorders. 6-11 later. No systemic manifestations were reported after
Herein, we reported three Egyptian cases with post- vaccination. Initial treatment included local steroids
COVID-19 vaccine olfactory and gustatory disorders. and vitamin B complex. No history of prior COVID-19
Vaccination was obligatory in their workplace. Smell infection was documented. Only minimal improvement
and taste disorders developed within days following in olfactory function was reported over the past 2 years.
administration of the second dose of the AstraZeneca/ Presentation in February 2023 was due to persistent
Oxford vaccine in 2021. In some cases, these disorders anosmia and severe parosmia for 20 months. The SOIT
persisted for years. Repeated nasal swabs and polymerase score showed anosmia with a result of 4 out of 16. Both
chain reaction (PCR) tests for SARS-CoV-2 were negative flavor and taste sensations remained intact.
at symptom onset, excluding the possibility of COVID-19 2.3. Case 3
infection. There was no history of comorbid medical,
neurological, or other conditions that might cause smell A 48-year-old male developed anosmia 10 days after
and taste disorders, such as allergies, infections, sinusitis, receiving the second dose of the AstraZeneca/Oxford
trauma, dry mouth, medications, and specific treatments. vaccine (August 2021, administered in Kuwait). A history of
Multiple ENT consultations were performed. Nasal myalgia and fatigue after vaccination was reported, which
endoscopy, computed tomography of the nasal cavities, resolved completely within 1 week. Two previous episodes
anterior cranial fossa, and sinuses, and magnetic resonance of COVID-19 infection were documented. The first episode
imaging (MRI) of the brain, including olfactory bulbs and occurred in February 2020 and was manifested by fever,
tracts, revealed no abnormalities. They presented to the flu-like symptoms, myalgia, cough, and loss of smell and
ENT outpatient clinic because of persistent disorders lasting taste. The second episode occurred in January 2021 and
several years after the initial onset. Clinical evaluation at presented with fever, myalgia, fatigue, flu-like symptoms,
the presentation included neurological evaluation and and cough. Viral manifestations in both episodes resolved
objective testing of olfactory and gustatory function using completely within 7 – 15 days. Presentation in August 2024

Volume 8 Issue 3 (2025) 102 doi: 10.36922/ITPS025140020