WASHINGTON – Sensory symptoms, including loss of taste and smell, sometimes accompany COVID-19, but a new study has found that COVID-19 can also infect cells in the inner ear, causing hearing problems and balance in some COVID-19 patients.
In the study, published on October 29, researchers at MIT and Massachusetts Eye and Ear looked at symptoms of hearing and balance in patients with COVID-19. The team also studied inner ear tissue and cells in humans and mice to determine the effect of the virus.
Ten adult patients who developed audio-vestibular dysfunction within three weeks of being diagnosed with COVID-19, confirmed by PCR or serum antibody test, were studied. Hearing loss ranged from mild to severe.
CT scan of the inner ear (Photo by: BSIP / Universal Images Group via Getty Images)
The results, published in the journals of the National Institutes of Health and “Communication medicine“, found nine of 10 patients with tinnitus – a ringing or buzzing noise in one or both ears. And six patients experienced dizziness – a sudden sensation of spinning.
âThe timing of symptom onset has suggested a correlation between COVID-19 infection and hearing loss,â said Dr. Brian Doctrow, Ph.D. with the National Institutes of Health, wrote.
Researchers have found that infection with COVID-19 requires certain proteins on the surface of the host cell. They found these proteins on two types of inner ear cells: hair cells and Schwann cells.
The team also developed inner ear tissue models that they could use for further investigation. They took human skin cells which were reprogrammed to become stem cells. They then directed the stem cells to develop into precursors of hair cells or Schwann cells.
Like human inner ear samples, these cells had the proteins necessary for infection. COVID-19 infected hair cell precursors and, to a lesser extent, Schwann cell precursors.
“The virus was able to infect cells resembling hair cells in organoids,” the NIH wrote. âTogether, these results indicate that SARS-CoV-2 infection of the inner ear is a cause of the hearing and balance problems associated with COVID-19. ”
While other senses like taste and smell have been more widely studied and reported, the symptoms of hearing and balance associated with COVID-19 have not been studied as extensively.
Still, the overall percentage of COVID-19 patients with ear-related problems is unknown.
“This work now paves the way for working not only with SARS-CoV-2 but also with other viruses that affect hearing,” noted Dr. Lee Gehrke, principal investigator of the study.
Another senior researcher, Konstantina Stankovic, told FOX News the team now hopes to use their human cell models to test possible treatments for inner ear infections caused by COVID-19 and other viruses.
This story was reported from Los Angeles. FOX News contributed.