A small study has shown that COVID-19 can cause inner ear infections and possibly trigger a host auditory problems.
Researchers at Massachusetts Eye and Ear and Massachusetts Institute of Technology (MIT), examined 10 Covid patients who reported a variety of ear-related symptoms.
The virus can infect inner ears cells, particularly hair cells, and cause hearing and balance problems.
According to the team, these findings are why COVID-19 patients have reported hearing impairment, tinnitus and dizziness, as well as difficulties with balance.
A new study revealed that inner ear cells are rich in proteins that coronaviruses need to enter and infect cells. This could explain why COVID-19 suffers have experienced hearing loss, tinnitus or dizziness, as well as balance problems (file image).
Dr Konstantina and Dr Lee Gherke were co-lead authors. They had been studying how viruses like mumps or hepatitis affect hearing prior to the pandemic.
In March 2020, after seeing coronavirus sufferers report hearing loss, dizziness, or tinnitus, the team decided to focus their attention on Covid.
Stantovic, who was previously chief of otology and neurotology at Massachusetts Eye and Ear and is currently chair of the Department of Otolaryngology Head and Neck Surgery at Stanford University School of Medicine, stated in a statement that it was unclear at the time if this was causally related.
The study was published in Communications Medicine. It involved the use of new cellular models for human inner ear cells as well as hard-to-find human inner ear cells.
According to them, other studies have been hindered by the absence of inner ear tissues.
Gehrke, a professor at MIT’s Institute for Medical Engineering and Science, stated that ‘having models is the first step.’ This work also opens a path for working with other viruses that affect hearing.
They took stem cells from humans and transformed them into ‘pluripotent’ stem cells. These cells can take on many forms in the body.
Researchers transformed stem cells into various types of inner ear cells, including hair cells and supporting cells. They could also be used to grow nerve fibers, Schwann cells, and 2D layers or 3D organoids.
The cells were then taken form the 10 Covid patients who underwent surgery for vertigo attacks and a tumor that causes severe hearing loss, dizziness, or both.
The team discovered that both human ear samples and models had hair cells with the same proteins as the Schwann cells. This allowed the coronavirus to enter and infect the cells.
This is particularly important as hair cells are essential for people to maintain balance and understand their head movement.
They could not transmit the virus to other types of cells.
It isn’t clear how the virus gets in to the body. It may enter the inner ear through a tube that connects the nose to the middle, or escape from the nose.
Another theory is that the virus escapes from the nose via small openings around the olfactory and cranial nerves.
Researchers are not able to determine the percentage of patients with the virus who have hearing problems. This problem is made worse by the lack of testing in the early stages of the pandemic.
Stankovic stated that the reason for this was initially because routine testing was not possible for patients with COVID. Additionally, patients who were suffering from more life-threatening complications were less likely to pay attention to their hearing loss or tinnitus.
“We don’t know the incidence, but our findings really call to increase attention to audiovestibular signs in people with Covid exposure.
