There has not yet been a big study on how common it is for people who have had Covid-19 to experience hearing loss, but a few small studies point to a possible link.
A team in England, UK, asked Covid-19 patients eight weeks after they’d been discharged from the hospital whether they’d experienced any hearing changes or ringing in their ears. Of the 138 patients in the study, published in the International Journal of Audiology, 13% said yes.
Doctors can’t say for sure that the virus attacks the inner ear. Doing a biopsy of the inner ear can be dangerous, as it risks damaging the tissue.
The researchers also performed procedures on the bodies of three people who had died after a Covid-19 infection to see if they could find the virus in the inner ears.
In two of the three cadavers, they found the novel coronavirus in the middle ear and mastoid bone in the skull, which is located just behind the ear. The study was published in JAMA Otolaryngology — Head and Neck Surgery.
A member of the team said while other viruses have been known to cause sudden hearing loss, “personally I’m suspicious that [the novel coronavirus] has the potential to be worse.”
The researcher said the reason is that the coronavirus is known to cause blood clots in other areas of the body, and he thinks that could be happening in the “extremely small blood vessels” in the inner ear.
Kevin Munro, an audiological scientist who co-authored the study in England, told CNN he thinks that theory makes sense.
“The capillaries in the inner ear are the smallest in the human body, so it wouldn’t take much to block them,” he said.