A Case Report of Sudden Sensorineural Hearing Loss (SSNHL) After Administration of the COVID-19 Vaccine

Abstract

Since the issuance of the emergency use authorization (EUA) of 3 coronavirus disease 2019 (COVID-19) vaccines, there have been over 180 million individuals fully vaccinated in the United States (US). With the increasing administration of COVID-19 vaccinations, there have been over 550,000 adverse events reported in the Vaccine Adverse Event Reporting System (VAERS) with approximately 230,000 experienced after receipt of the Pfizer-BioNTech COVID-19 Vaccine as of September 23^rd 2021. Audio-vestibular symptoms (including Sudden Sensorineural Hearing Loss (SSNHL)) secondary to immunizations has previously been evaluated. However, this report describes the first case of bilateral sudden sensorineural hearing loss potentially due to the Pfizer-BioNTech COVID-19 vaccine. We further review the available literature regarding the treatment of Sudden Sensorineural Hearing Loss, and the association of SSNHL with previous immunizations and COVID-19 infection. Lastly, we hypothesize the underlying potential mechanisms between SSNHL and the Pfizer-BioNTech COVID-19 vaccine.

Introduction

As of September 2021, coronavirus disease 2019 (COVID-19) has affected over 40 million individuals in the United States (US) and has led to over 600,000 deaths nationwide.¹ To circumvent the ongoing spread of COVID-19, an emergency use authorization (EUA) of the Pfizer-BioNTech COVID-19 vaccine was authorized by the Food and Drug Administration (FDA) on December 11, 2020.² Within 5 months of the initial EUA of the Pfizer-BioNTech COVID-19 vaccine, there have been 2 additional COVID-19 vaccines that were approved for EUA by Moderna and Johnson and Johnson/Janssen.^3,4 Due to the EUA of 3 COVID-19 vaccines in the US, there have been over 182 million individuals fully vaccinated, accounting for 54% of the total US population.¹ With the increasing administration of COVID-19 vaccinations, there have been over 550,000 adverse events reported in the Vaccine Adverse Event Reporting System (VAERS) with approximately 230,000 experienced after receipt of the Pfizer-BioNTech COVID-19 Vaccine as of September 23^rd 2021. In regards to audio-vestibular symptoms, a recent preliminary analysis of association between COVID-19 vaccination and sudden hearing loss using VAERS reported approximately 40 total cases with 28 cases occurring after receipt of the Pfizer-BioNtech COVID-19 vaccine and 12 cases occurring after receipt of the Moderna COVID-19 vaccine.⁵

Audio-vestibular symptoms, such as sudden sensorineural (“inner ear”) hearing loss (SSNHL, commonly known as sudden deafness, is an unexplained, rapid loss of hearing either all at once or over a few days.⁶ It is defined as a hearing loss of at least 30 decibels (dB) in at least 3 consecutive frequencies that has developed within 3 days and could be caused by some viral infections.^7,8 Previous anecdotal reports have led to concerns of the causation of SSNHL to vaccinations which led to a case-centered analysis conducted by Baxter et. al. in which it was found that there was no evidence of increased risk of immunization compared with matched controls. Furthermore, the investigators found the odds ratios for vaccination 1 week prior to SSNHL were .965 (95% confidence interval, .61-1.50) for trivalent inactivated influenza vaccine (TIV); .842 (.39-1.62) for tetanus, reduced diphtheria, and reduced acellular pertussis; and .454 (.08-1.53) for zoster vaccine.^9-14

Recently, a systematic review by Almufarrij et. al. analyzed numerous case reports/series and cross sectional studies to determine the prevalence of audio-vestibular symptoms with COVID-19 infection and it was found that the pooled estimate of prevalence based primarily on retrospective recall of symptoms, was 7.6% (CI: 2.5-15.1), 14.8% (CI: 6.3-26.1) and 7.2% (CI: .01-26.4), for hearing loss, tinnitus and rotatory vertigo, respectively.¹⁶ However, there is limited published literature with the exception of VAERS that have reported sudden sensorineural hearing loss after receiving the Pfizer-BioNTech COVID-19 vaccine. Thus, we present a case of bilateral sudden sensorineural hearing loss potentially due to the Pfizer-BioNTech COVID-19 vaccine.

Case Presentation

A 41 year-old female with migraines and history of left worse than right, hearing loss, presented to the otolaryngology outpatient clinic following 1 day of audio-vestibular symptoms of bilateral sudden sensorineural hearing loss. The patient received the Pfizer-BioNTech COVID-19 vaccine on January 28, 2021 and the onset of symptoms occurred on February 27, 2021, 30 days following the second dose. Other pertinent symptoms at the initial receipt of the Pfizer-BioNTech COVID-19 vaccine were fatigue and arm soreness of the left deltoid. Her past medical history before arriving at the otolaryngology outpatient clinic was migraine, which has been controlled on fremanezumab-vfrm (Ajovy^TM) 225 mg subcutaneously monthly and a tympanoplasty and ossicular chain reconstruction in the middle ear due to a cholesteatoma back in 2016. During the 2016 examination the patient presented with hearing within normal limits sloping to severe sensorineural hearing loss with good speech discrimination in the right ear and a mild sloping to moderately severe conductive/mixed hearing loss with good speech discrimination in the left ear.

During the initial examination (Figure 1), on March 1^st, 2021, the patient presented with a sudden change in hearing from her right ear, tinnitus, dizziness and vertigo. The ear canals were patent, non-inflamed and the tympanic membrane was visualized. A complete audiological evaluation was conducted at that time. The results revealed a moderate sloping to a severe essentially sensorineural hearing loss with poor speech discrimination and Type A tympanogram in the right ear and a moderately severe rising to moderate sloping to a profound conductive/mixed hearing loss with excellent speech discrimination and Type A tympanogram in the left ear. Hearing had decreased from a previously documented audiogram from June 4^th, 2020. Patient was treated with oral prednisone as described in detail in the below treatment section and was instructed to follow up in 2 weeks.

Figure 1.

Audiogram for right ear.

The patient returned on March 15, 2021, after finishing the prescribed dose of corticosteroids with no relief of audio- vestibular symptoms and unremarkable ear canals, to complete a follow up audiogram. The audiogram revealed a moderate sloping to a severe essentially sensorineural hearing loss with poor speech discrimination and Type A tympanogram in the right ear and a moderate sloping to a profound conductive/mixed hearing loss with excellent speech discrimination and Type A tympanogram in the left ear. The hearing was consistent with the previous audiogram from March 1^st, 2021. The risks and benefits of intratympanic injections were reviewed with the patient and she consented to move forward with the injections for 3 consecutive weeks. The process of administration is described below in the treatment section. Additionally, an MRI of the brain and internal auditory canals (IACs) with and without contrast was prescribed and completed on March 5^th, 2021 in which results were unremarkable.

On March 19^th, 2021 and March 24^th, 2021, the patient returned to clinic with no/minimal improvement in hearing for her second and third intra-tympanic injection and the same administration process was followed.

On March 31^st, 2021, the patient returned for a follow up audiogram after all intra-tympanic steroid injections for right ear were completed. The audiogram revealed a moderate sloping to a profound sensorineural hearing loss with poor speech discrimination and Type A tympanogram in the right ear and a moderately severe rising to moderate sloping to a profound conductive/mixed hearing loss with excellent speech discrimination and Type A tympanogram in the left ear. The audiogram was consistent with the previous audiogram from March 15^th, 2021. At this time the patient was recommended to make an appointment for a Hearing Aid Evaluation to further discuss options to improve the patient’s hearing and to take otic drops for 1 week and subsequently follow up in 2 months.

On May 19^th, 2021, the patient returned for 2-month follow up with the physician to have an audiogram completed. She presented with worsening right-sided tinnitus with fluctuation and associated tingling of the right side of the face post right-sided sudden sensorineural hearing loss. The audiogram revealed a moderately severe sloping to a severe sensorineural hearing loss with no measurable speech discrimination (very distorted and caused pain) and Type A tympanogram in the right ear and a moderate sloping to a profound conductive/mixed hearing loss with excellent speech discrimination and Type A tympanogram in the left ear. Pure tone thresholds were consistent with previous audiological findings, however, there was a significant decrease in her speech discrimination, in which that the patient could not repeat back any of the bi-syllabic words presented to her. At this time, she was recommended to continue use of her hearing aids and to follow up with a neuro-otologist if symptoms persist.

Treatment

The patient was initially treated with an oral prednisone 60 mg daily for 7 days, 40 mg daily for 3 days, 20 mg daily for 3 days, 10 mg daily for 3 days with minimal improvement starting on March 1^st, 2021.

Subsequently, the patient was treated with dexamethasone once every 4-5 days with no further improvement. The first dose was given on March 15^th, 2021, the second dose was given on March 19^th, 2021 and the third and final dose was given on March 24^th, 2021. During each weekly visit, the tympanic membrane was visualized under binocular microscopy. Topical Phenol solution was applied to the tympanic membrane in the anterior-inferior quadrant. A small myringotomy was then made in the anesthetized portion. A secondary myringotomy was made in the posterior-inferior quadrant. Using a 27-gauge needle, Dexamethasone 10 mg/mL was injected into the middle ear space. The patient was kept in the supine position and instructed not to swallow. The patient was then discharged after a short observation period.

Once all injections were completed the patient was also prescribed .3% ofloxacin to instill 5 drops by otic route twice daily into the affected right ear.

After all medical treatments were explored, the patient was recommended to be evaluated for bilateral hearing aids or a CROS (contralateral routing of signals) device.

Outcome and Follow-Up

There was no clear etiology for the audio-vestibular symptoms that was found, however, it was hypothesized that the symptoms could have been secondary to the administration of the Pfizer-BioNTech COVID-19 vaccine. Furthermore, there is a need for further investigation to determine whether previous middle-ear related hearing loss could predispose patients to audio-vestibular symptoms secondary to the administration of the Pfizer-BioNTech COVID-19 vaccine.

Discussion

Audio-vestibular symptoms secondary to COVID-19 infection is an area of ongoing research in the field of otolaryngology with multiple reports of hearing loss (eg sudden sensorineural), tinnitus and rotary vertigo; however, the literature is sparse in relation to audio-vestibular symptoms secondary to the COVID-19 vaccine.¹⁵ A systematic literature review was performed using the PubMed database from 1950 to April 2021. The key words used were the following: ‘hearing loss’, ‘COVID-19’, ‘coronavirus’, ‘sensorineural hearing loss’, ‘COVID-19 vaccine’. The literature was reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. According to the literature review, the patient case report described above is the first reported case of audiovestibular symptoms secondary to the COVID-19 vaccine.

Potential mechanisms of audio-vestibular disorders secondary to COVID-19 infection have been described in previous published literature. Lang et. al. postulated that cochleitis or neuritis caused by viral involvement of the inner ear or the vestibulocochlear nerve could potentially lead to vertigo, tinnitus and hearing loss. Secondly, antibodies or T-cells may misidentify inner ear antigens as the virus, leading to accidental damage to the inner ear.¹⁶ Thirdly, cochlea and semicircular canals have no collateral blood supply leaving them susceptible to ischemia.¹⁷ Additionally, cardiovascular manifestations could result in inner ear thrombosis or hypoxia leading to hearing loss.^15,18-20 Lastly, Degen et. al. proposed that a sequelae of immune-mediated disorders (eg hyperproduction of proinflammatory cytokines) may negatively affect the audio-vestibular system.²¹

Potential mechanisms of audio-vestibular disorders secondary to the COVID-19 vaccine can be extracted from the mechanism of action of the Pfizer-BioNTech COVID-19 vaccine. For example, findings from studies conducted in the United States and Germany among healthy men and women showed that 2 30-μg doses of BNT162b2, Pfizer-BioNTech COVID-19 vaccine, elicited high SARS-CoV-2 neutralizing antibody titers and robust antigen-specific CD8⁺ and Th1-type CD4⁺ T-cell responses.²² With the combination of the neutralizing antibody titers and increased antigen specific CD8⁺ and CD4⁺ T-cell responses, there is potential for immune-mediated disorders, such as, hyperproduction of proinflammatory cytokines similarly to other vaccine literature.^23,24 Another potential mechanism may be antibodies or T-cells misidentifying inner ear antigens as the virus leading to accidental damage to the inner ear with the introduction of SARS-CoV-2 neutralizing antibodies, CD8⁺ and CD4⁺ T-cell responses.¹⁶

The treatment courses for the patient aligned with the 2019 Clinical Practice Guideline for Sudden Hearing Loss as it is recommended as an option for clinicians to offer corticosteroids as initial therapy to patients with SSNHL within 2 weeks of symptom onset.¹⁷ Similarly, Formeister et. al. reported that 75% of the patients that were included in their preliminary analysis received corticosteroids.⁵ The treatment regimen was started in our patient and previous reports as corticosteroids are known to have sites of action in the inner ear in viral, vascular, syphilitic, autoimmune, endolymphatic hydrops (Meniere’s disease), and other etiologies of hearing loss.^25,26 Subsequently, intratympanic corticosteroids for salvage therapy were recommended as the patient had incomplete recovery from SSNHL 2 to 6 weeks after onset of symptoms.¹⁷ Additional treatment options that could potentially have been explored was the use of the combination of hyperbaric oxygen therapy (HBOT) combined with corticosteroid therapy within 2 weeks of onset of SSNHL. However, given the small number of patients in the trials reviewed, methodological shortcomings, and poor reporting, there remains uncertainty regarding the real benefit of HBOT for SSNHL.^17,27 There is substantial cost, potential adverse effects, uncertainty regarding the clinical significance of the hearing improvement in treated patients, and the confounding effect of concurrent steroid therapy.¹⁷

The Naranjo Algorithm, or Adverse Drug Reaction Probability Scale, is a method for assessing whether there is a causal relationship toward an unexpected clinical event and a medication using a simple questionnaire to assign probability scores.²⁸ The pertinent findings of the Naranjo Algorithm for the described patient in the causal relationship between SSNHL and the Pfizer-BioNTech COVID-19 vaccine include the adverse event occurring after the administration of the COVID-19 vaccine and the confirmation of the adverse event by an objective finding of the audiogram of the right ear (Figure 2). Of note, the onset of SSNHL for our patient occurred at 30 days which is longer compared to Formeister et. al. who reported a mean (range) SSNHL onset after vaccine dose of 4 days (0 - 21 days).⁶ Therefore, the Naranjo Adverse Drug Reaction Probability Scale resulted as a possible causal relationship between SSNHL and the Pfizer-BioNTech COVID-19 vaccine (Figure 2).

Figure 2.

Naranjo Adverse Drug Reaction Probability Scale.

Conclusion

Audio-vestibular symptoms (including sudden sensorineural hearing loss) remain a topic in question in terms of its clinical relationship with COVID-19 infection and COVID-19 vaccines. Potential mechanisms have been postulated for both scenarios, however, for audio-vestibular symptoms secondary to COVID-19 vaccines there is very limited literature with hyper-production of cytokines or a misinterpretation of antigens leading to accidental damage to the inner ear. Audio-vestibular symptoms (sudden sensorineural hearing loss) secondary to the COVID-19 vaccine are an area of research with further investigations being warranted for its mechanism and treatment options. The significance of this causation is to be considered very low in the light that is a single report in 182 million vaccinations.

ORCID iD

Justin Andrade https://orcid.org/0000-0003-2382-9201