Can COVID-19 cause hearing loss?
The arrival of COVID-19 coronavirus (SARS-CoV-2) has taken the world by storm. With such a new virus, scientists and doctors are learning new things about the symptoms, outcomes, and management almost every day. A few months ago, it was discovered that the loss of the sense of smell and/or taste can be a symptom of the virus. If these senses can be affected, is it possible that hearing may be affected by the virus as well? Can COVID-19 cause hearing loss? We looked at the research that is currently available to see what has been discovered so far.
Viruses and Hearing Loss
One of the reasons scientists and doctors are concerned about COVID-19 causing hearing loss is because other viruses are known to affect the ears and hearing. Viruses like Rubella and Cytomegalovirus can cause hearing loss in babies. HIV and some Herpes viruses are known to increase chances of hearing loss in adults and children. Some viruses can also lead to sudden-onset hearing losses. These include Measles, Mumps, Varicella Zoster Virus (another type of Herpes), and West Nile Virus. Because viruses like these can affect both the cochlea and the auditory nerve, we are interested to see whether this new virus might also attack the hearing system in the same or similar way.
Back in April, the first case of hearing loss in a COVID-19 patient was reported in an academic journal. This case was an older woman in Thailand, who experienced a change in hearing after her COVID-19 diagnosis. The hearing loss persisted after she recovered from the virus. This single case study was the first documented sign that there may be a link between COVID-19 and hearing loss. Just 8 days later, another article described 20 young adults who were positive for COVID-19 but had no symptoms. Objective and subjective hearing tests were performed on these patients and a control group. High-frequency cochlear hair cell damage was significantly worse in the COVID-19 positive group when compared to the control group. Based on this finding, it appeared that COVID-19 can indeed affect hearing.
6 weeks later, in May, a case was presented at the Mayo Clinic of one individual who experienced severe to profound hearing loss in both ears after being hospitalised with COVID-19 pneumonia. This patient had no history of hearing loss before. Case presenters were unable to determine whether the hearing loss was as a result of the virus, or from the intravenous antibiotics and other medications that were administered, some of which are known to be toxic to the ears.
In June, an Iranian team reported a group of 6 COVID-19 patients who presented with mild virus symptoms, all of whom reported hearing-related change since the onset of the virus. 4 of them experienced tinnitus, 2 experienced vertigo, and all 6 presented with mild to moderate hearing loss in one ear. This team also reported anecdotally that they have noted even more COVID-19 patients with similar hearing loss. Two days later the International Journal of Infectious Diseases reported a single case of asymptomatic COVID-19 who experienced a sudden sensorineural hearing loss. The most recent report came on the 8th of July, another case study of a single patient with asymptomatic COVID-19 who experienced sudden sensorineural hearing loss and tinnitus in one ear.
What do these studies tell us?
These studies and cases are few, and all involved either single patients or very small sample sizes. However, they are coming from all over the world, with similar experiences in different population groups. These studies indicate that there may well be a connection between COVID-19 and hearing loss, but is it enough to say for sure that COVID-19 causes hearing loss? Not yet.
When considering a virus like COVID-19 and hearing loss, we must remember that there may be other factors that could contribute to the loss of hearing. In an earlier paragraph, we mentioned certain medications that are known to be ototoxic. Unfortunately, with such a new virus, doctors are still learning how best to treat it, and many different drugs have been tried. Some of these, like Chloroquine and Hydroxychloroquine, are derivatives of Quinine, which is known to be mildly ototoxic, especially if it is presented in high doses. Hydroxychloroquine has been found to be ineffective against COVID-19, although it is still being widely used in many countries. Patients are also still commonly being prescribed antibiotics like Azithromycin for COVID-19, which has also been flagged for being toxic to the ears in the past. In May and June, many COVID-19 patients were being treated with a combination of Hydroxychloroquine and Azithromycin as the first line of treatment. This raises the question of whether the known ototoxicity of these drugs may be part of the problem people are experiencing with their hearing. Time, and deeper, larger-scale studies, will show us whether there will be any long-term effects of this treatment.
So, does COVID-19 cause hearing loss?
The jury is still out on this one. Although studies have been reported, they are all small and short term. Certain cases and findings are indicating that hearing loss, perhaps in one ear only, or perhaps with a sudden onset, could be a side effect or even a symptom of COVID-19. In addition, audiologists and ENT specialists around the world are noting anecdotal cases of people with COVID-19 and new hearing loss. However, many larger-scale studies are needed to know for sure whether COVID-19 and hearing loss are truly linked.
We will keep you informed about any further studies in this area as they are released. Click subscribe or follow us on Facebook or Instagram to make sure you never miss a post. Comment below, or contact us if you’d like any more information.