The reversible tinnitus and cochleopathy followed first-dose AstraZeneca COVID-19 vaccination

Audiovestibular adverse events following COVID-19 vaccinations

INTRODUCTION

Evidence regarding audiovestibular adverse events post COVID-19 vaccination to date has been inconclusive regarding a potential association. This study aimed to determine if there was an increase in audiovestibular events following COVID-19 vaccination in South-eastern Australia during January 2021-March 2023.

METHODS

A multi-data source approach was applied. First, a retrospective observational analysis of spontaneous reports of audiovestibular events to a statewide vaccine safety surveillance service, SAEFVIC. Second, a self-controlled case series analysis using general practice data collected via the POpulation Level Analysis and Reporting (POLAR) tool.

RESULTS AND CONCLUSIONS

This study is the first to demonstrate an increase in general practice presentations of vertigo following mRNA vaccines (RI = 1.40, P <.001), and tinnitus following both the Vaxzevria® adenovirus vector and mRNA vaccines (RI = 2.25, P <.001 and 1.53, P <.001 respectively). There was no increase in hearing loss following any COVID-19 vaccinations. Our study, however, was unable to account for the potential of concurrent COVID-19 infections, which literature has indicated to be associated with audiovestibular events. Healthcare providers and vaccinees should be alert to potential audiovestibular complaints after COVID-19 vaccination. Our analysis highlights the importance of using large real-world datasets to gather reliable evidence for public health decision making.

Vestibular disorders following BNT162b2 mRNA COVID-19 vaccination: A retrospective case series

BACKGROUND

There are few publications regarding manifestations of vestibular disorders (VDs) following BNT162b2 mRNA COVID-19 vaccination.

PURPOSE

We describe cases of VD potentially related to BNT162b2 vaccination and calculate its reporting rate, in order to enlarge knowledge about this adverse effect.

METHODS

A retrospective analysis of cases of VD following BNT162b2 vaccination reported to the pharmacovigilance centre of Georges-Pompidou European Hospital (France), in 2021 was performed. In order to identify these cases from the pharmacovigilance database containing all our registered cases, we used the Standardised MedDRA Query (SMQ) 'vestibular disorders'. Then we analysed cases with vestibular symptoms, based on the association of typical manifestations. The reporting rate was calculated based on the number of VD cases and the number of vaccinated patients.

RESULTS

Among 6608 cases reported to our centre related to COVID-19 vaccines during 2021, 34 VDs associated with BNT162b2 administration were included. They were mainly reported in females (79%), 62% occurred after the first dose and 32% were serious. Symptoms had completely resolved in 13 cases (38%). Vertigo was the most common symptom followed by balance disorders. Three patients received second dose without reappearance of VD. The final diagnosis was reported in 10 patients (six cases of vestibular neuritis, two cases of central VD, two cases of benign paroxysmal positional vertigo). The regional reporting rate was 26 [95% CI: 17-34] cases of VD per 1 million persons vaccinated.

CONCLUSION

Although the relationship between vaccination and VD cannot be established, clinicians should be aware of this rare adverse effect.

NEURO-COVAX: An Italian Population-Based Study of Neurological Complications after COVID-19 Vaccinations

OBJECTIVE

In this Italian population-based study, we aimed to evaluate the neurological complications after the first and/or second dose of COVID-19 vaccines and factors potentially associated with these adverse effects.

METHODS

Our study included adults aged 18 years and older who received two vaccine doses in the vaccination hub of Novegro (Milan, Lombardy) between 7 and 16 July 2021. The NEURO-COVAX questionnaire was able to capture the neurological events, onset and duration. That data that were digitized centrally by the Lombardy region were used to match the demographic/clinical characteristics and identify a vulnerability profile. Associations between vaccine lines and the development of complications were assessed. Digital healthcare system matching was also performed to evaluate severe neurological complications (Guillain-Barrè syndrome, Bell's palsy, transverse myelitis, encephalitis) and the incidence of hospital admissions and/or the mortality rate after two doses of the vaccines.

RESULTS

The NEURO-COVAX-cohort included 19.108 vaccinated people: 15.368 with BNT162b2, 2077 with mRNA-1273, 1651 with ChAdOx1nCov-19, and 12 with Ad26.COV2.S who were subsequently excluded. Approximately 31.2% of our sample developed post-vaccination neurological complications, particularly with ChAdOx1nCov-19. A vulnerable clinical profile emerged, where over 40% of the symptomatic people showed comorbidities in their clinical histories. Defining the neurological risk profile, we found an increased risk for ChAdOx1nCov-19 of tremors (vs. BNT162b2, OR: 5.12, 95% CI: 3.51-7.48); insomnia (vs. mRNA-1273, OR: 1.87, 95% CI: 1.02-3.39); muscle spasms (vs. BNT162b2, OR: 1.62, 95% CI: 1.08-2.46); and headaches (vs. BNT162b2, OR: 1.49, 95% CI: 0.96-1.57). For mRNA-1273, there were increased risks of parethesia (vs. ChAdOx1nCov-19, OR: 2.37, 95% CI: 1.48-3.79); vertigo (vs. ChAdOx1nCov-19, OR: 1.68, 95% CI: 1.20-2.35); diplopia (vs. ChAdOx1nCov-19, OR: 1.55, 95% CI: 0.67-3.57); and sleepiness (vs. ChAdOx1nCov-19, OR: 1.28, 95% CI: 0.98-1.67). In the period that ranged from March to August 2021, no one was hospitalized and/or died of severe complications related to COVID-19 vaccinations.

DISCUSSION

This study estimates the prevalence and risk for neurological complications potentially associated with COVID-19 vaccines, thus improving the vaccination guidelines and loading in future personalized preventive medicine.

COVID-19 and tinnitus: an initiative to improve tinnitus care

OBJECTIVE

To investigate the effects of COVID-19 on individuals with tinnitus and their views to guide future tinnitus care.

DESIGN

A mixed-methods cross-sectional research design.

STUDY SAMPLE

An online survey was completed by 365 individuals with tinnitus from Australia and other countries.

RESULTS

Tinnitus was reported to be more bothersome during the pandemic by 36% of respondents, whereas 59% reported no change and 5% reported less bothersome tinnitus. Nearly half of the respondents had received COVID-19 vaccination(s) and 12% of them reported more bothersome tinnitus while 2% developed tinnitus post-vaccination. Australian respondents spent less time in self-isolation or quarantine and saw fewer change in in-person social contact than respondents from other countries. More than 70% of respondents thought that tinnitus care services were insufficient both before and during the pandemic. Regarding their opinions on how to improve tinnitus care in the future, five themes including alleviation of condition, government policies, reduced barriers, self- and public-awareness, and hearing devices were identified.

CONCLUSIONS

A majority of respondents did not perceive any change in tinnitus perception and one-third of respondents had worsened tinnitus during the pandemic. To improve tinnitus care, better awareness and more accessible resources and management are crucial.

Tinnitus cases after COVID-19 vaccine administration, one institution's observations

OBJECTIVE

After the role out of the COVID-19 vaccine in the United States, there has been increase in case reports of tinnitus attributed to the vaccine reported. We present our institution's experience over the initial 13 month period the vaccines were available.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary academic otology and general otolaryngology practice.

PATIENTS

Patients who received a COVID-19 vaccine and a tinnitus diagnosis code.

INTERVENTIONS

Observation, steroids (oral and intratympanic), diagnostic imaging and audiometry.

MAIN OUTCOME MEASURES

Patients who received a COVID-19 vaccine in the time frame of 12/1/2020-12/31/21 with a diagnosis of tinnitus, an audiogram, and at least one visit with one of our Otolaryngologists were included in the study. Twenty-seven of the 1254 patients identified met these criteria. The patients ranged in age from 41 to 84 years old including seven male and twenty female patients. Sixteen received the Pfizer vaccine, seven received the Moderna vaccine and four patients received the Janssen vaccine.

CONCLUSIONS

No definite correlation could be established between COVID-19 vaccine and tinnitus. Any concurrent sudden hearing loss should be treated as usual with oral or intratympanic steroids. Health care providers should be aware of the tinnitus onset and if new or recent onset, to refer for prompt audiogram and Otolaryngology evaluation.

Prevalence of New-Onset Tinnitus after COVID-19 Vaccination with Comparison to Other Vaccinations

OBJECTIVE

To investigate how often patients are diagnosed with new-onset tinnitus within 21 days after COVID-19 vaccination in comparison to after three other common vaccinations: influenza, Tdap (tetanus, diphtheria, and acellular pertussis), and polysaccharide pneumococcus.

METHODS

The TriNetX Analytics Network, a federated health research network that aggregates the de-identified electronic health record (EHR) data of over 78 million patients, was queried for patients receiving each vaccination. Instances of new-onset tinnitus within 21 days of vaccination were recorded and reported.

RESULTS

Out of 2,575,235 patients receiving a first dose of the mRNA COVID-19 vaccine without any prior tinnitus diagnosis, 0.038% (95% CI: 0.036%-0.041%) of patients had a new diagnosis of tinnitus within 21 days. There was a higher risk of a new tinnitus diagnosis after the influenza vaccine (RR: 1.95, 95% CI: 1.72-2.21), Tdap vaccine (RR: 2.36, 95% CI: 1.93-2.89), and pneumococcal vaccine (RR: 1.97, 95% CI: 1.48-2.64) than after the first dose of the COVID-19 vaccine. There was a lower risk of a new tinnitus diagnosis after the second dose of COVID-19 than after the first dose (RR: 0.80, 95% CI: 0.71-0.91).

CONCLUSION

The rate of newly diagnosed tinnitus acutely after the first dose of the COVID-19 vaccine is very low. There was a higher risk of newly diagnosed tinnitus after influenza, Tdap, and pneumococcal vaccinations than after the COVID-19 vaccine. The present findings can help to address COVID-19 vaccine hesitancy during the ongoing pandemic.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 133:1722-1725, 2023.

Characterization of otologic symptoms appearing after COVID-19 vaccination

OBJECTIVES

Anecdotal reports of sudden sensorineural hearing loss (SSNHL) following COVID-19 vaccination have emerged in the otolaryngology community. Studies have demonstrated no association between COVID-19 vaccination and SSNHL. We aim to characterize the spectrum of otologic symptoms following COVID-19 vaccination.

METHODS

A cross-sectional study of patients seen in the otology clinic at an academic center was performed. Patients completed a questionnaire on the development of new otologic symptoms within 4 weeks of COVID-19 vaccination. Diagnostic and audiometric data was collected retrospectively for patients reporting otologic symptoms.

RESULTS

Between May and July 2021, 500 patients were screened. Median age was 56.6 years old, with 59.4 % female and 40.2 % male. 420 patients (84.0 %) were vaccinated, with 58.4 % receiving Pfizer, 29.1 % receiving Moderna, and 3.8 % receiving Johnson & Johnson. 61 patients (14.5 %) reported one or more otologic symptoms within 4 weeks of vaccination, including 21 (5.0 %) with hearing loss, 26 (6.2 %) with tinnitus, 33 (7.9 %) with dizziness, and 19 (4.5 %) with vertigo. Of the 16 patients (3.2 %) reporting tinnitus with no associated hearing loss, 8 were diagnosed with subjective tinnitus and 4 were diagnosed with temporomandibular joint syndrome. Of the 18 patients reporting hearing loss, 11 had exacerbations of underlying pathologies (e.g. Meniere's disease, presbycusis) and 7 were newly diagnosed with SSNHL (1.4 %).

CONCLUSIONS

Patients reporting otologic symptoms following COVID-19 vaccination received various diagnoses of uncertain etiology. The incidence of SSNHL in these patients is comparable to the general otology patient population. Additional studies are required to determine the incidence of specific diagnoses following vaccination.

A review of neurological side effects of COVID-19 vaccination

Following the COVID-19 virus epidemic, extensive, coordinated international research has led to the rapid development of effective vaccines. Although vaccines are now considered the best way to achieve collective safety and control mortality, due to the critical situation, these vaccines have been issued the emergency use licenses and some of their potential subsequence side effects have been overlooked. At the same time, there are many reports of side effects after getting a COVID-19 vaccine. According to these reports, vaccination can have an adverse event, especially on nervous system. The most important and common complications are cerebrovascular disorders including cerebral venous sinus thrombosis, transient ischemic attack, intracerebral hemorrhage, ischemic stroke, and demyelinating disorders including transverse myelitis, first manifestation of MS, and neuromyelitis optica. These effects are often acute and transient, but they can be severe and even fatal in a few cases. Herein, we have provided a comprehensive review of documents reporting neurological side effects of COVID-19 vaccines in international databases from 2020 to 2022 and discussed neurological disorders possibly caused by vaccination.

Co-VAN study: COVID-19 vaccine associated neurological diseases- an experience from an apex neurosciences centre and review of the literature

BACKGROUND

Recent studies have shown various neurological adverse events associated with COVID-19 vaccine.

OBJECTIVE

We aimed to retrospectively review and report the neurological diseases temporally associated with COVID-19 vaccine.

METHODS

We performed a retrospective chart review of admitted patients from 1st February 2021 to 30th June 2022. A total of 4672 medical records were reviewed of which 51 cases were identified to have neurological illness temporally associated with COVID-19 vaccination.

RESULTS

Out of 51 cases, 48 had probable association with COVID-19 vaccination while three had possible association. Neurological spectrum included CNS demyelination (n = 39, 76.5 %), Guillain-Barré-syndrome (n = 3, 5.9 %), stroke (n = 6, 11.8 %), encephalitis (n = 2, 3.9 %) and myositis (n = 1, 2.0 %). Female gender had a greater predisposition (F:M, 1.13:1). Neurological events were more commonly encountered after the first-dose (n = 37, 72.5%). The mean latency to onset of symptoms was 13.2 ± 10.7 days after the last dose of vaccination. COVIShield (ChAdOx1) was the most commonly administered vaccine (n = 43, 84.3 %). Majority of the cases with demyelination were seronegative (n = 23, 59.0 %) which was followed by anti-Myelin oligodendrocyte-glycoprotein associated demyelination (MOGAD) (n = 11, 28.2 %) and Neuromyelitis optica (NMOSD) (n = 5, 12.8 %). Out of 6 Stroke cases, 2 cases (33.3 %) had thrombocytopenia and coagulopathy. At discharge, 25/51 (49.0 %) of the cases had favourable outcome (mRS 0 to 1). Among six patients of stroke, only one of them had favourable outcome.

CONCLUSION

In this series, we describe the wide variety of neurological syndromes temporally associated with COVID-19 vaccination. Further studies with larger sample size and longer duration of follow-up are needed to prove or disprove causality association of these syndromes with COVID-19 vaccination.

Signaling COVID-19 Vaccine Adverse Events

Introduction

Statistical signal detection is a crucial tool for rapidly identifying potential risks associated with pharmaceutical products. The unprecedented environment created by the coronavirus disease 2019 (COVID-19) pandemic for vaccine surveillance predisposes commonly applied signal detection methodologies to a statistical issue called the masking effect, in which signals for a vaccine of interest are hidden by the presence of other reported vaccines. This masking effect may in turn limit or delay our understanding of the risks associated with new and established vaccines.

Objective

The aim is to investigate the problem of masking in the context of COVID-19 vaccine signal detection, assessing its impact, extent, and root causes.

Methods

Based on data underlying the Vaccine Adverse Event Reporting System, three commonly applied statistical signal detection methodologies, and a more advanced regression-based methodology, we investigate the temporal evolution of signals corresponding to five largely recognized adverse events and two potentially new adverse events.

Results

The results demonstrate that signals of adverse events related to COVID-19 vaccines may be undetected or delayed due to masking when generated by methodologies currently utilized by pharmacovigilance organizations, and that a class of advanced methodologies can partially alleviate the problem. The results indicate that while masking is rare relative to all possible statistical associations, it is much more likely to occur in COVID-19 vaccine signaling, and that its extent, direction, impact, and roots are not static, but rather changing in accordance with the changing nature of data.

Conclusions

Masking is an addressable problem that merits careful consideration, especially in situations such as COVID-19 vaccine safety surveillance and other emergency use authorization products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-022-01186-z.

Persisting, unilateral tinnitus 22 days after first dose of an mRNA-based SARS-CoV-2 vaccine

Objectives:

Although vaccination with vector-based or mRNA-based SARS-CoV-2 vaccines is usually well tolerated, they are not free of side effects. Some of these side effects can be severe and concern the primary care physician, otorhinolaryngologist, and the neurologist. Persisting, unilateral tinnitus time-linked to the first dose and worsening after the second dose of an mRNA-based SARS-CoV-2 vaccine has not been reported.

Study Design:

Case report.

Methods:

Routine tests were applied to investigate the patient.

Results:

A 35-year-old male experienced sudden onset of right-sided tinnitus, diffuse headache, and ear respectively facial pressure 22 days after the first dose of an mRNA-based SARS-CoV-2 vaccine. Since symptoms worsened after the second dose, 28 days later, the patient started a self-medication with non-steroidal anti-inflammatory drugs, without benefit. After an otolaryngologist suspected Meniere’s disease, prednisone was given for 5 days with significant improvement. After discontinuation of steroids, however, previous symptoms recurred with similar intensity as before. Cetirizin and loratadin were started resulting in complete resolution of headache and pressures but persistence of tinnitus. After exclusion of various differentials, a causal relation between clinical presentation and vaccination was suspected.

Conclusions:

SARS-CoV-2 vaccination can be followed by unilateral persisting tinnitus, headache, and ear respectively facial pressure. Since steroids and anti-histamines had a beneficial effect, an immunological pathophysiology is quite likely.

Adverse Audio-Vestibular Effects of Drugs and Vaccines Used in the Treatment and Prevention of COVID-19: A Review

(1) Background: The purpose of this article is to review pharmacological treatments for COVID-19 (currently approved by the EMA (European Medical Agency) and FDA (Food and Drug Administration)) and highlight their potential audio-vestibular side-effects as an ototoxic adverse reaction. (2) Methods: Review of the available literature in the scientific databases PubMed, ResearchGate, Scopus, and ScienceDirect, and in summaries of product data sheets. (3) Results: In accordance with EBM (evidence-based medicine) the treatment of COVID-19 by using lopinavir/ritonavir, chloroquine and hydroxychloroquine, azithromycin, favipiravir, amantadine, oseltamivir, and ivermectin is no longer recommended for patients suffering from COVID-19 due to a lack of clinical data, publications, and recommendations. There were 39 publications and 15 summaries of product characteristics (as other sources of data) which were also used in this analysis. Adverse events could be permanent or disappear over time. Following treatment for COVID-19, the most frequent adverse audio-vestibular reactions reported in clinical trials and publications in the area of audiology and otorhinolaryngology were: dizziness, blurry vision with dizziness, nasopharyngitis, dysgeusia, and tinnitus. As far as vaccines are concerned, dizziness as an ototoxic effect was uncommon and occurs only in hypersensitive people who experience anaphylactic shock. (4) Conclusions: The ototoxicity of the drugs discussed here does not have as severe symptoms as the drugs used in the treatment of COVID-19 in 2020 (e.g., hydroxychloroquine), and relates mainly to disorders of the vestibulocochlear system. However, there is still a need to monitor ototoxic side-effects because of potential interactions with other ototoxic drugs. Many of the drugs approved by EMA and FDA are new, and not every side-effect is known.

Audiovestibular Disorders after COVID-19 Vaccine: Is There an Association?

The SARS-CoV-2 vaccination campaign is probably one of the most historic public hygiene measures in modern medicine. The drama of the pandemic has forced the scientific community to accelerate the development and commercialization of vaccines, thereby enhancing the phases of active surveillance. Among the adverse events following immunization (AEFI) reported, those of an audiovestibular interest, such as sudden sensorineural hearing loss (SSNHL), tinnitus, dizziness, and vertigo, constitute a very small percentage. There are many plausible etiological hypotheses, and scientific research needs to pay more attention to the correct collection of data, which up until now have often been inadequate and fragmented, on which to base future studies. SSNHL, new onset tinnitus, vertigo, and dizziness require a prompt evaluation, while the proposed treatment is the same as it is for events unrelated to vaccination. These are uncommon adverse events, and the risk rates for these diseases have not increased in conjunction with the COVID-19 vaccinations, therefore there is no justification of any hesitation towards the vaccination campaign.

Vestibular Cochlear Manifestations in COVID-19 Cases

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a high transmissible infectious disease that primarily impacts the respiratory system and leads to death as it worsens. Ever since the World Health Organization declared the disease as a global pandemic, the pathophysiology, clinical manifestations, and disease prognosis has been discussed in various literature. In addition to impaired respiratory health, the symptoms also indicated the involvement of the cardiovascular and neurological system after SARS-CoV-2 infection. Despite the pulmonary, cardiovascular, and neurological complications, many reports also revealed the prevalence of vestibulocochlear symptoms like dizziness, vertigo, vestibular neuritis, sudden sensorineural hearing loss, and tinnitus. Though many clinical reports and scientific reviews reported the vestibular and cochlear impairments associated with coronavirus disease 2019 (COVID-19) infection, the underlying pathological mechanisms are still unclear and unexplored. In this review, we discussed the published clinical reports, research articles, and literature reviews related to vestibulocochlear manifestations following SARS-CoV-2 infections. We also summarized the current knowledge about the prevalence, epidemiological and clinical features, and potential pathological mechanisms related to vestibular and cochlear manifestations resulting from COVID-19 infections.

Neuro-Ophthalmic Implications of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Related Infection and Vaccination

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic created a unique opportunity to study the effects of infection and vaccination on disease. The year 2020 was dominated by infection and its consequences. The year 2021 was dominated by vaccination and its consequences. It will still take several years for full maturation of databases required for robust epidemiological studies. Therefore, this review on the implications for neuro-ophthalmology draws on resources presently available including reported adverse reactions to vaccination. Illustrative clinical cases are presented.The spectrum of pathology following infection with SARS-CoV-2 falls into 4 main categories: autoimmune, vascular, sequelae of brain damage, and miscellaneous. This review is exhaustive, but the most common conditions discussed relate to headaches and associated symptoms; vertigo, diplopia, and nystagmus; vascular complications of the eye and brain; cranial nerve (mono-)neuropathies; photophobia, ocular discomfort, and optic neuritis. Of the 36 main adverse reactions reviewed, vaccine-induced immune thrombotic thrombocytopenia is a novel complication requiring specific hematological management. Updated diagnostic criteria are summarized. It is relevant to remember taking a medication history because of side effects and to recognize the relevance of comorbidities. The clinical assessment can frequently be performed virtually. Consensus recommendations on telemedicine and the virtual assessment are summarized in a practical and compressed format.The review concludes with an epidemiological tetralogy to interrogate, in future studies, associations with (1) SARS-CoV-2 pandemic infection, (2) SARS-CoV-2 worldwide vaccination, and (3) the possibility of a rebound effect of infections in the pandemic aftermath.

Tinnitus, Sudden Sensorineural Hearing Loss, and Vestibular Neuritis As Complications of the Astra Zeneca COVID-19 Vaccine

BACKGROUND

Sudden sensorineural hearing loss is most commonly defined as a sensorineural hearing loss of 30dB or greater over at least three contiguous audiometric frequencies occurring within a 72-hr period. The Astra Zeneca COVID-19 vaccine is suspicious of causing thrombotic complications following its administration, and could theoretically induce hearing loss by damaging the hearing organs through this mechanism, as well as vestibular damage through similar mechanisms.

MATERIAL AND METHODS

We reviewed the files of patients with otological symptoms after exposure to the Astra Zeneca COVID-19 vaccine during the year 2021.

CASE SERIES

We studied a total of six cases with otologic symptoms temporally related to the Astra Zeneca COVID-19 vaccine. We report four cases of patients presenting with hearing loss and tinnitus a few days after the second dose of the Astra Zeneca vaccine, and one case with the same symptoms after the first dose. Four cases were successfully treated with steroids; however, one case presented to the office two months after the onset of symptoms and did not improve with treatment. We also report the first case of vestibular neuritis temporally related to the administration of the first dose of the vaccine, which also had a good outcome after medical treatment.

CONCLUSIONS

Prompt treatment in the present cases was a factor associated with a good prognosis.

Acute Vertigo After COVID-19 Vaccination: Case Series and Literature Review

Objective: The aim of this study was to present some cases of acute vertigo potentially related to the coronavirus disease 2019 (COVID-19) vaccine and review the available literature about cochleovestibular dysfunction after the COVID-19 vaccination.

Methods: In the period from May to July 2021, we evaluated 33 patients (mean age 54.3 ± 14.1) with “acute vertigo” post COVID-19 vaccination. A detailed medical history was taken on comorbidities, types of vaccines received, and symptoms associated. All patients underwent otoneurological evaluation, such as head impulse test, nystagmus evaluation, test of skew (HINTS) examination. Head shaking test-induced nystagmus, hyperventilation-induced nystagmus, and parossistic positional nystagmus were studied to search for vestibular impairment.

Results: Symptoms included 16 patients (48.5%) with objective vertigo, 14 patients (42.4%) with subjective vertigo, and 3 patients (9.1%) with dizziness. Of the associated ear, nose, and throat (ENT) symptoms, the most expressed was tinnitus (18.2%). Bedside examination showed absent nystagmus in 7 patients (21.2%), 9 patients (27.3%) had horizontal or rotatory nystagmus, 17 patients (51.5%) had a vertical or oblique nystagmus, negative HST, or “central HINTS.”

Discussion and Conclusions: The 9 patients had an evoked nystagmus pathognomonic for benign paroxysmal positional vertigo; in the remaining 17 cases, peripheral vestibular dysfunction could be excluded and central disorder may be suggested. Due to the prevalence of nystagmus of non-peripheral origin, a central nervous system involvement could not be excluded. However, due to the small sample size, a definite cause–effect relationship between vaccination and vertigo cannot be inferred. In light of expected third dose, large-scale and well-designed studies are needed to better define possible adverse reactions of the COVID-19 vaccine.

Spectrum of neurological complications following COVID-19 vaccination

COVID-19 vaccines have brought us a ray of hope to effectively fight against deadly pandemic of COVID-19 and hope to save lives. Many vaccines have been granted emergency use authorizations by many countries. Post-authorization, a wide spectrum of neurological complications is continuously being reported following COVID-19 vaccination. Neurological adverse events following vaccination are generally mild and transient, like fever and chills, headache, fatigue, myalgia and arthralgia, or local injection site effects like swelling, redness, or pain. The most devastating neurological post-vaccination complication is cerebral venous sinus thrombosis. Cerebral venous sinus is frequently reported in females of childbearing age, generally following adenovector-based vaccination. Another major neurological complication of concern is Bell's palsy that was reported dominantly following mRNA vaccine administration. Acute transverse myelitis, acute disseminated encephalomyelitis, and acute demyelinating polyneuropathy are other unexpected neurological adverse events that occur as result of phenomenon of molecular mimicry. Reactivation of herpes zoster in many persons, following administration of mRNA vaccines, has been also recorded. Considering the enormity of recent COVID-19-vaccinated population, the number of serious neurological events is miniscule. Large collaborative prospective studies are needed to prove or disprove causal association between vaccine and neurological adverse events occurring vaccination.