Hearing loss and other auditory problems are strongly associated with COVID-19 according to a systematic review of research evidence led by The University of Manchester and NIHR Manchester Biomedical Research Centre (BRC) scientists. Professor Kevin Munro and PhD researcher Ibrahim Almufarrij found 56 studies that identified an association between COVID-19 and auditory and vestibular problems.
They pooled data from 24 of the studies to estimate that the prevalence of hearing loss was 7.6%, tinnitus was 14.8% and vertigo was 7.2%.
However, the team – who followed up their review carried out a year ago – described the quality of the studies as fair. Their data primarily used self-reported questionnaires or medical records to obtain COVID- 7 19-related symptoms, rather than the more scientifically reliable hearing tests.
The study was funded by is NIHR Manchester Biomedical Research Centre.
Munro, professor of audiology at The University of Manchester and Manchester BRC hearing health lead said: “There is an urgent need for a carefully conducted clinical and diagnostic study to understand the long-term effects of COVID-19 on the auditory system.
“It is also well-known that viruses such as measles, mumps and meningitis can cause hearing loss; little is understood about the auditory effects of the SARS-CoV-2 virus.”
“Though this review provides further evidence for an association, the studies we looked at were of varying quality so more work needs to be done.”
Munro, is currently leading a year-long UK study to investigate the possible long-term impact of COVID-19 on hearing among people who have been previously treated in hospital for the virus. His team hope to accurately estimate the number and severity of COVID-19 related hearing disorders in the UK, and discover what parts of the auditory system might be affected. They will also explore the association between these and other factors such as lifestyle, the presence of one or more additional conditions and critical care interventions.
A recent study led by Munro, suggested that more than 13% of patients who were discharged from a hospital reported a change in their hearing.
Almufarrij said: “Though the evidence is of varying quality, more and more studies are being carried out so the evidence base is growing. What we really need are studies that compare COVID-19 cases with controls, such as patients admitted to hospital with other health conditions.
“Though caution needs to be taken, we hope this study will add to the weight of scientific evidence that there is a strong association between COVID-19 and hearing problems.”
Munro added: “Over the last few months I have received numerous emails from people who reported a change in their hearing, or tinnitus after having COVID-19.
“While this is alarming, caution is required as it is unclear if changes to hearing are directly attributed to COVID-19 or to other factors, such as treatments to deliver urgent care.”
Study review details
One year on: an updated systematic review of SARS-CoV-2, COVID-19 and audio-vestibular symptoms
Ibrahim Almufarrij, Kevin Munro
The aim was to systematically review the literature to December 2020, in order to provide a timely summary of evidence on COVID-19 and audio-vestibular symptoms.
The protocol was registered in the International Prospective Register of Systematic Reviews. The methods were developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Risk of bias was assessed using the National Institute of Heath quality assessment tools.
After rejecting 850 records, 28 case reports/series and 28 cross-sectional studies met the inclusion criteria.
There are multiple reports of hearing loss (e.g., sudden unilateral), tinnitus and rotatory vertigo in adults having a wide range of COVID-19 symptom severity. The pooled estimate of prevalence, based primarily on retrospective recall of symptoms, is 7.6% (CI: 2.5-15.1), 14.8% (CI: 6.3-26.1) and 7.2% (CI: 0.01-26.4), for hearing loss, tinnitus and rotatory vertigo, respectively. However, these could be an over-estimate because it was not always clear that studies were reporting a change in symptom.
There are multiple reports of audio-vestibular symptoms associated with COVID-19. However, there is a dearth of high-quality studies comparing COVID-19 cases and controls.
The suicide of Kent Taylor, the founder and CEO of the Texas Roadhouse restaurant chain, has drawn attention to a possible link between COVID-19 and tinnitus, the medical term for a constant ringing in the ears. The New York Times reports that Taylor suffered from a variety of symptoms following his illness, including severe tinnitus, his family said in a statement, adding that his suffering had become “unbearable.”
Whether tinnitus is linked to COVID-19 – and if so, how often it occurs – is an unanswered question. Neither the World Health Organisation nor the US Centres for Disease Control and Prevention describes tinnitus as a symptom, although auditory problems are common in other viral infections.
But the NYT reports, tinnitus is on the list of symptoms of long COVID published by the UKʼs National Health Service, along with fatigue, shortness of breath, dizziness and more. And a few recent case reports and studies have hinted at a potential link.
“In the 24 hours since we published, Iʼve received about 100 emails,” Kevin Munro. “Almost of all of them were people saying, ‘I was so happy to read about this, because my doctor thought I was crazy when I mentioned tinnitus and now I know Iʼm not the only one.”
The University of Manchester material
The University of Manchester study review (Restricted access)
International Journal of Audiology letter (Open access)
Full New York Times report (Restricted access)