The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily causes respiratory illness, but its effects on the body are complex. Beyond the well-known symptoms like cough and fever, many individuals have reported problems with their hearing and balance systems during or immediately following an infection. Scientific investigation suggests a direct or indirect link between COVID-19 and a range of auditory and vestibular symptoms, indicating the virus can affect the delicate structures of the ear, leading to temporary or persistent issues.
The Most Commonly Reported Ear Issues
The most frequent ear-related complaint associated with COVID-19 is tinnitus, which is the perception of sound, like ringing, buzzing, or hissing, without any external source. This persistent sound can occur in one or both ears and often fluctuates in intensity, causing considerable distress for patients.
Another serious, though less common, symptom is sudden sensorineural hearing loss (SSNHL), which involves damage to the inner ear or the nerve pathways leading to the brain. This type of hearing loss can range from mild to profound and, in some instances, may even be the initial or only symptom of the viral infection. Vertigo and dizziness are also frequently reported, indicating that the vestibular system, which controls balance, is affected by the virus.
Many individuals also experience a sensation of aural fullness or ear pain, known as otalgia. This feeling of blockage is often a result of eustachian tube dysfunction, where inflammation and congestion in the upper respiratory tract block the tube connecting the middle ear to the back of the nose. While this is frequently temporary, it can lead to pressure changes and discomfort.
How SARS-CoV-2 May Affect the Ear
The mechanisms by which SARS-CoV-2 may lead to ear dysfunction involve a combination of direct viral effects and the body’s inflammatory response. One central hypothesis points to the virus’s ability to infect cells within the inner ear directly. Studies have confirmed that inner ear tissue, including the delicate hair cells responsible for hearing and balance, expresses the angiotensin-converting enzyme 2 (ACE2) receptor and the transmembrane protease serine 2 (TMPRSS2) enzyme.
These two proteins are the primary molecular entry points for the SARS-CoV-2 virus into human cells. Research using human inner ear models has demonstrated that the virus can infect these specific cell types, suggesting a direct pathway for cellular damage within the cochlea and vestibular system. The destruction of these cells directly correlates with symptoms like sensorineural hearing loss and vestibular dysfunction.
A second mechanism involves the body’s overactive inflammatory response, often termed a “cytokine storm.” When the immune system aggressively fights the virus, it releases inflammatory molecules that can cause systemic damage, including to the highly sensitive inner ear structures. This excessive inflammation can disrupt the environment of the inner ear, even without the virus directly entering the tissue, leading to damage to the auditory and balance nerves.
Furthermore, the vascular effects of COVID-19 are thought to play a role in ear damage. The virus is known to affect the lining of blood vessels, increasing the risk of blood clotting and microvascular damage. If the tiny blood vessels that supply the inner ear are blocked or damaged, the resulting lack of oxygen and nutrients can cause injury to the cochlea and the auditory nerve. This microvascular injury is a proposed cause for sudden hearing loss observed in some patients.
Ear Problems in Post-Acute COVID Syndrome
For a subset of individuals, ear-related symptoms do not resolve after the acute infection phase ends, instead persisting as part of Post-Acute COVID Syndrome (PASC), commonly known as Long COVID. Symptoms like chronic tinnitus, persistent dizziness, and imbalance can linger for weeks or months after the virus has been cleared from the body.
This persistence suggests that the underlying damage or immune dysregulation continues long after the initial illness. Studies have found that individuals with PASC exhibit altered central auditory pathways, which may explain the increased prevalence and severity of tinnitus. While peripheral hearing thresholds may appear normal, the processing of sound in the brain can be affected, potentially contributing to persistent symptoms.
The lingering nature of these symptoms presents challenges in diagnosis and management, as they are often subjective and difficult to treat. Persistent aural fullness or hearing loss may require specialized audiological assessment and intervention. The focus in managing these chronic issues shifts to addressing the long-term nerve or inflammatory damage that continues to affect the delicate structures responsible for hearing and balance.