Pneumonia, heart muscle inflammation, and exhaustion. These are all well-known symptoms of COVID-19.
But vertigo and dizziness? Nobody has really studied that until now.
A new study that just appeared in the journal Communications Medicine investigates the connection between COVID-19 and vertigo. And the results are quite interesting.
A research team led by MIT and the Stanford University School of Medicine noted that many COVID patients had reported struggling with things like vertigo, tinnitus, and hearing loss. In this study, they described 10 such cases.
When considered alongside serious complications like pneumonia and heart muscle inflammation, you can see why this has not really been studied up to now. But using a fairly simple study in the laboratory, these researchers found that these complaints might be valid.
Since they had previously developed cellular models of the human inner ear for research on the ability of other infections like mumps and hepatitis to cause vertigo and hearing loss, they were in a good position to study this question. All they needed to do was apply the SARS-CoV-2 virus to these models.
When they did so, they immediately discovered that this virus could certainly infect the cells of the inner ear, including the hair cells responsible for balance. They also showed that the human inner ear had the right types of cells to facilitate entry of the virus into this space.
The hair cells and Schwann cells in the inner ear have the surface proteins that must be present for the SARS-CoV-2 virus to enter them.
Specifically, they have the ACE2 receptor, which appears on the exterior of cells, along with enzymes called furin and transmembrane protease serine 2, which the virus hijacks to invade and take over the cell.
In other words, our inner ears have laid-out welcome mats for the SARS-CoV-2 virus to enter.
If the laboratory inner ear model sounds too remote for your liking, they also tested their hypothesis on real human and mouse inner ear tissue to confirm their findings.
The human inner ear tissue was obtained from patients who had undergone surgery for various inner ear disorders. This is the only way to obtain inner ear tissue, because researchers clearly cannot take it out through your ear channel. So these scientists were well-placed with the right resources to answer this question.
To enter our inner ears, it is easy for the virus to get in through our mouths or noses, giving it a direct route to our ears.
The scientists acknowledged that they didn’t know the numbers of COVID-19 patients who suffered from vertigo and hearing loss, although their evidence is compelling that it can and does happen.