, experts have found, adding that such problems need early detection and urgent treatment.
The coronavirus has been found to affect the body in myriad ways, from a loss of taste and smell to organ damage.
Now doctors have reported fresh evidence that Covid could also affect hearing.
Writing in the journal BMJ Case Reports, experts at University College London report the case of a 45-year-old man with asthma who was admitted to intensive care with Covid, ventilated, and given drugs including the antiviral remdesivir and intravenous steroids.
A week after leaving intensive care he developed a ringing sound – tinnitus – and then hearing loss in his left ear.
The team say none of the medications the man was given would be expected to cause damage to his hearing, while he had no problems with his ear canals or ear drums. Further investigation showed no sign of autoimmune problems, while he did not have flu or HIV – conditions previously linked to hearing loss. What’s more, the man had never had hearing problems before.
Subsequent tests revealed the man had sensorineural hearing loss in his left ear – a situation where the inner ear or the nerve responsible for sound is inflamed or damaged. This was treated with steroids with partial success.
The case is the first such incident to be reported in the UK, although a small number of similar reports have emerged from other countries.
Dr Stefania Koumpa, a co-author of the study, said it is not yet known how Covid might cause hearing loss, but there are possible explanations.
“It is possible that the Sars-Cov-2 virus enters inner ear cells and brings about cell death, and/or causes the body to release inflammatory chemicals called cytokines that can be toxic to the inner ear,” she said. “Steroids likely help by reducing inflammation and therefore production of cytokines.”
The team say Covid patients in intensive care should be asked about hearing loss and referred for emergency treatment.
“Even single-sided hearing loss has great consequences on one’s quality of life, if not promptly treated,” said Koumpa.
Kevin Munro, professor of audiology at the University of Manchester, who was not involved in the work, said it is known that other viruses, including measles and mumps, can affect hearing, while he has been contacted by a large number of Covid survivors reporting a change in their hearing or tinnitus.
Work from his team previously found that 16 of 121 patients admitted to hospital with Covid, and who completed a survey, reported hearing problems about two months after discharge.
Munro said his team is now investigating the prevalence and causes of such problems, noting it is unclear whether they are down to the virus itself, the immune system response, stress, or even treatments for Covid – or whether it could simply be that hearing problems become apparent in a noisy hospital where individuals wear masks.
“I think there’s likely to be lots of explanations for why people were reporting problems,” he said.