COVID-19 & Hearing Loss
COVID-19 is an illness that has taken over all of our lives for over a year now. The common symptoms that people experience are a high temperature, a new, continuous cough and a loss or change to their sense of smell or taste. But a different side effect has been reported; hearing loss. Viruses such as measles, mumps and meningitis are known to sometimes cause hearing loss. The virus that is responsible for COVID-19 could also cause damage to hearing. It has mainly been reported anecdotally, with a recent study led by Professor Munro, suggesting that more than 13% of patients who were discharged from hospital reported a change to their hearing.
The reports so far form only anecdotal evidence, and have yet to be fully researched scientifically. However, a small study has suggested links between COVID-19 and other hearing problems, such as tinnitus. The study conducted by Anglia Ruskin University found that out of the patients who had COVID-19 and tinnitus, 40% of them reported experiencing a worsening of their tinnitus. There have been enough reports for scientists to decide that the potential link between COVID-19 and hearing loss needed further investigation.
Most research has come from case studies of individuals reporting sudden hearing loss after having COVID-19. The next major study will be to investigate the possible long-term impact of COVID-19 on hearing, led by researchers at NIHR Manchester Biomedical Research Centre. This research aims to accurately estimate the number, and severity of COVID-19 related hearing disorders in the UK. It will also study what parts of the auditory system might be affected, and explore the association between these and other factors such as lifestyle, the presence of one or more additional conditions (comorbidities) and critical care interventions.
Whilst the evidence is mainly anecdotal, there have been some scientific reports that have studied this phenomena. Most of these studies do, however, report that further research is needed to confirm the theory. For example, one study found that high frequency pure-tone thresholds were significantly worse even in the test group of people with COVID-19 who showed no symptoms. This suggests that the COVID-19 infection could have harmful effects on cochlear hair cell functions despite being asymptomatic.
Since it is still not determined that COVID-19 directly causes hearing loss or tinnitus, it is difficult to say why some people experience this as a side effect. Some research suggests that hearing loss and tinnitus occur as a side effect of the medication used to treat COVID-19. For example, drugs that can be used to treat COVID-19 such as quinine, cholorquine and hydroxychloroquine all come with high risks of hearing loss, ringing in the ears or vertigo and dizziness as a side effect. Additionally, when suffering with COVID-19, the patients’ oxygen levels tend to drop quite low. Low oxygen levels, or hypoxia, can cause long-term hearing decline and this could be the reason for COVID-19 patients reporting hearing loss.
Bottom Line of COVID-19 & Hearing Loss
Overall, whilst there are many anecdotal links between COVID-19 and hearing loss, it is very clear that further research is needed. With hearing loss already being the most common sensory issue, it is important to make sure research into these topics is thoroughly looked into.
As the pandemic wears on and research shifts to long-term effects, we’ll likely begin to learn more.