COVID-19 News

Olfactory Hallucinations Following COVID-19 Vaccination

Fed Pract. 2023 September;40(9) | doi:10.12788/fp.0410

Author(s):

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.

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References

1. Xu S, Huang R, Sy LS, et al. COVID-19 vaccination and non-COVID-19 mortality risk - seven integrated health care organizations, United States, December 14, 2020-July 31, 2021. MMWR Morb Mortal Wkly Rep. 2021;70(43):1520-1524. Published 2021 Oct 29. doi:10.15585/mmwr.mm7043e2

2. Der-Martirosian C, Steers WN, Northcraft H, Chu K, Dobalian A. Vaccinating veterans for COVID-19 at the U.S. Department of Veterans Affairs. Am J Prev Med. 2022;62(6):e317-e324. doi:10.1016/j.amepre.2021.12.016

3. Bagnato F, Wallin M. COVID-19 vaccine in veterans with multiple sclerosis: protect the vulnerable. Fed Pract. 2021;38(suppl 1):S28-S32. doi:10.12788/fp.0113

4. Işlek A, Balcı MK. Phantosmia with COVID-19 related olfactory dysfunction: report of nine cases. Indian J Otolaryngol Head Neck Surg. 2022;74(suppl 2):2891-2893. doi:10.1007/s12070-021-02505-z

5. Konstantinidis I, Tsakiropoulou E, Hähner A, de With K, Poulas K, Hummel T. Olfactory dysfunction after coronavirus disease 2019 (COVID-19) vaccination. Int Forum Allergy Rhinol. 2021;11(9):1399-1401. doi:10.1002/alr.22809

6. Keir G, Maria NI, Kirsch CFE. Unique imaging findings of neurologic phantosmia following Pfizer-BioNtech COVID-19 vaccination: a case report. Top Magn Reson Imaging. 2021;30(3):133-137. doi:10.1097/RMR.0000000000000287

7. Garg RK, Paliwal VK. Spectrum of neurological complications following COVID-19 vaccination. Neurol Sci. 2022;43(1):3-40. doi:10.1007/s10072-021-05662-9

The rapid development of multiple vaccines for COVID-19 significantly contributed to reducing the morbidity and mortality associated with COVID-19 infection.¹ The vaccination campaign against COVID-19 started in December 2020 within the US Department of Veterans Affairs (VA) health care system with the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines followed by the Johnson & Johnson (J&J) vaccine in March 2021.^2,3

Because of the importance of maintaining a safe vaccination campaign, surveillance reports documenting cases of malignant or benign adverse effects (AEs) are fundamental to generate awareness and accurate knowledge on these newly developed vaccines. Here we report the case of a veteran who developed olfactory hallucinations following the administration of the J&J COVID-19 vaccine.

Case Presentation

A 39-year-old veteran with a history of tension-type headaches presented to the neurology clinic with concern of a burning smell sensation in the absence of an identifiable source. He first noticed this symptom approximately 3 weeks after he received the J&J COVID-19 vaccine about 4 months prior. At the symptom’s first occurrence, he underwent a nasal swab antigen COVID-19 test, which was negative. Initially, symptoms would occur daily lasting about 1 hour. Thereafter, they started to decrease in duration, frequency, and intensity, and about 11 months postvaccination, milder episodes were occurring 1 to 2 times weekly. These episodes lasted nearly 2 years (21 months postvaccination). They happened randomly during the day and were not associated with any other symptoms. Specifically, there were no headaches, loss of consciousness, abnormal movements, nausea, vomiting, photophobia or phonophobia, or alteration of consciousness, such as confusion or drowsiness during or after the events. Additionally, there were no clear triggers the veteran could identify. The veteran did not sustain any head injuries or exposure to toxic odors before the onset of symptoms.

At the time of his presentation to the clinic, both his general and neurological examinations were unremarkable.

Brain magnetic resonance imaging (MRI) showed chronic sinusitis but no other abnormalities (Figure 1), though the phantosmia persisted after the sinusitis had been treated with a course of doxycycline. An electroencephalogram (EEG) was obtained and was unremarkable as well (Figure 2). Notably, however, the EEG did not capture the episodes of phantosmia.

Together the clinical and paraclinical evidence along with the timing of symptom onset in relation to vaccination point toward a new onset of phantosmia as an AE of the J&J COVID-19 vaccine.

New COVID vaccines force bivalents out

Olfactory Hallucinations Following COVID-19 Vaccination

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Case Presentation

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