In this Q&A, otolaryngologist Eric Smouha, MD, answers our questions about the possible association between COVID-19 infection and audio-vestibular symptoms, including the effects of SARS-CoV-2 virus on the inner ear and implications for clinical practice.
Findings from a systematic review of reports, including a collection of 28 case reports/series and 28 cross-sectional studies suggest that a variety of audio-vestibular symptoms may be associated with COVID-19 infections.1
Symptoms may include:
- Hearing loss
- Tinnitus: ringing or buzzing noise in one or both ears that may be constant or come-and-go, which is often associated with hearing loss
- Rotatory vertigo: a sensation of rotation resembling the feeling of being on a merry-go-round
Eric Smouha, MD, is an attending otolaryngologist at ENT and Allergy Associates and a clinical professor of otolaryngology at Mount Sinai Health System (New York, NY). Consultant360 reached out to Dr Smouha to answer our questions about the effect the SARS-CoV-2 virus may have on the inner ear.
Consultant360: Please describe the audio-vestibular symptoms that audiologists and otolaryngologists have been seeing in patients who have had COVID-19 infection.
Eric Smouha, MD: A systematic review of reports on COVID-19 and audio-vestibular symptoms found a 7.6% incidence of hearing loss, a 14.8% incidence of tinnitus, and a 7.2% incidence of vertigo in patients with COVID-19 infection.1 The authors commented that these figures could be an overestimate because the source papers did not always differentiate between new and preexisting symptoms.
At this point in time, many people have been infected with the SARS-CoV-2 virus, and most are symptomatic with fever and upper respiratory symptoms. Some have had cardiovascular and neurovascular symptoms that have resulted in severe illness. A significant percentage have remained asymptomatic. Because testing is usually only performed in symptomatic or exposed individuals, the true incidence of organ involvement is unknown. A 7% incidence of audio-vestibular symptoms is cited in this paper, but this is an estimate at best.1 These symptoms are self-reported, and some of these may have been coincidental and not actually caused by the SARS-CoV-2 virus. We need to accumulate more data before we know for certain.
Consultant360: What effects does the SARS-CoV-2 virus have on the inner ear?
ES: A recent article by Stankovic and colleagues at Harvard University showed that the SARS-CoV-2 virus is capable of infecting hair cells from the human inner ear in cell cultures.2 This is the best available evidence of the infectious potential of the virus. But what happens in the real world is still not well known. I think it is accepted by the medical community that hearing loss, tinnitus, and dizziness can be caused by Covid-19 infection. The incidence is not known, and neither is the prognosis. Patients with these symptoms are often treated with steroids and some improve. It is difficult to know in these cases whether the coronavirus was the culprit, as the same symptoms may occur with similar incidence in the general population. The time course is important. If the auditory symptoms began during the acute infection, then the virus is likely to be the cause. If they began days or weeks later, then this is less likely.
A separate but related issue is whether the COVID-19 vaccine can cause audio-vestibular symptoms. The best available studies have shown that the incidence of these symptoms is similar in vaccinated and unvaccinated patients. The incidence of these symptoms is very low in both populations. Currently, there is overwhelming clinical evidence that the COVID-19 vaccines have been effective in preventing severe illness, hospitalization, and death. Patients who remain reluctant to get vaccinated should be reassured that the chance of getting severe complications from the virus far outweighs the chance of complications from the vaccine.
Consultant360: How do the results of this study impact clinical practice?
ES: COVID-19 infection can affect the inner ear. Audio-vestibular symptoms can include hearing loss, tinnitus, vertigo, and imbalance. The incidence of these symptoms as a direct effect of the SARS-CoV-2 virus is low. The true incidence is not certain because we can only rely on patient's reports. Audio-vestibular symptoms in patients with COVID-19 infection should be treated with steroids. Some, but not all, will recover.
Vaccination remains the best defense against COVID-19 infection, and all patients should be encouraged to get vaccinated. Although audio-vestibular symptoms have been reported after COVID-19 vaccination, the incidence is low, and the risk of complications from the virus is much higher than from the vaccine.
Published in partnership with Consultant360. View the original Q&A and similar educational articles at consultant360.com
- Almufarrij I, Munro K. One year on: an updated systematic review of SARS-CoV-2, COVID019 and audio-vestibular symptoms. Int J Audiol. 2021;1499-2027. doi:10.1080/14992027.2021.1896793
- Jeong M, Ocwieja KE, Han D, et al. Direct SARS-CoV-2 infection of the human inner ear may underlie COVID-19-associated audiovestibular dysfunction. Commun Med. 2021;1(1):44. doi:10.1038/s43856-021-00044-w