COVID virus can infect inner ear, cause hearing loss, study finds
(Gray News) - A recent study found the virus that causes COVID-19 can infect cells of the inner ear, including hair cells, which are critical for both hearing and balance.
In a study of 10 COVID-19 patients who reported a variety of ear-related symptoms, researchers with the Massachusetts Institute of Technology and Massachusetts Eye and Ear said they found a pattern of infection in human inner ear tissue samples consistent with inner ear problems.
The study said several COVID patients developed issues with their ears - including hearing loss, tinnitus. dizziness and balance problems - which suggests that the SARS-CoV-2 virus may be able to infect the inner ear.
Before the COVID pandemic began, Lee Gehrke, a professor at MIT’s Institute for Medical Engineering and Science, and Konstantina Stankovic, a former associate professor at Harvard Medical School, began working together on a project to develop cellular models to study infections of the inner ear, MIT said.
Viruses such as cytomegalovirus, mumps and hepatitis can all cause deafness, the professors said.
In early 2020, after the SARS-CoV-2 virus emerged, Stankovic said she started to see patients who were experiencing hearing loss, tinnitus and dizziness who had tested positive for COVID.
Gehrke and Stankovic decided to use the model system they were working on to study the COVID infections, MIT said. And their research showed that the virus can infect the inner ear, specifically the hair cells and, to a lesser degree, Schwann cells, cells that keep peripheral nerve fibers alive.
“Having the models is the first step, and this work opens a path now for working with not only SARS-CoV-2 but also other viruses that affect hearing,” Gehrke said.
Nine of the 10 patients suffered from tinnitus, six experienced vertigo and all experienced mild to profound hearing loss.
Possible routes the virus can take to enter the ears include the eustachian tube, which connects the nose to the middle ear.
Stankovic said the virus may also be able to escape from the nose through small openings surrounding the olfactory nerves. That would allow it to enter the brain space and infect cranial nerves, including the one that connects to the inner ear.
“This article provides very compelling evidence that Sars-CoV-2 infects the inner ear, and might be causally related to the hearing and balance symptoms in a number of patients with COVID-19 infection,” said Yuri Agrawal, a professor of otolaryngology, head and neck surgery at Johns Hopkins School of Medicine.
Researchers said they hope to use their human cellular models to test possible treatments for the inner ear infections caused by SARS-CoV-2 and other viruses.
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