The Lingering Effects of COVID-19

“Because supplements and smell retraining are relatively benign and fairly inexpensive with minimal to no side effects, I recommend the combination to a lot of my patients,” Dr. Iloreta said.

A “really exciting new breakthrough in treating long COVID” is platelet-rich plasma (PRP) injections, Dr. Patel said. Her team evaluated the efficacy of intranasal PRP injections to treat COVID-19-related olfactory dysfunction that had persisted at least six months and had not responded to olfactory training or steroid rinses. Enrolled patients received intranasal injections of either PRP or sterile saline into their olfactory clefts every two weeks for six weeks. Three months after the first injection, 57.1% of the PRP group showed clinically significant improvement, compared to just 8.3% of the placebo group. The PRP group also experienced a 3.67- point greater improvement in olfaction (Int Forum Allergy Rhinol. 2022. doi:10.1002/alr.23116).

“These patients had already tried and failed to improve with olfactory training and budesonide irrigations. So, this intervention isn’t simply just another option, but one that has proven efficacy even in the face of other known standard options failing,” Dr. Patel said. She has since offered PRP injections to all patients with smell loss and is “seeing some continued good results,” she said.

Otologic Manifestations

Although the CDC does not include tinnitus, hearing loss, or balance problems on its list of long COVID symptoms, which it states is “not a comprehensive list,” evidence suggesting that COVID-19 can cause tinnitus, hearing loss, and vertigo is “mounting,” said Michael Brenner, MD, associate professor in the department of otolaryngology–head and neck surgery at the University of Michigan in Ann Arbor.

“There’s a high likelihood that this virus is capable of causing hearing loss,” he said. “A recent study in Communications Medicine implicated the coronavirus in hearing and balance disorders. It provided putative evidence that the SARSCoV- 2 virus can directly infect the inner ear. The work showed that adult human inner ear tissue expresses the receptors and cofactors required for SARS-CoV-2 viral entry, including angiotensin-converting enzyme 2 (ACE2) receptor, the transmembrane protease serine 2 (TMPRSS2), and FURIN cofactors. In addition, explanted human vestibular tissue can be infected by SARS-CoV-2.”

A 2021 systematic review and meta-analysis published by Cambridge University Press found a 3.1% event rate of hearing loss, 4.5% rate of tinnitus, and 12.2% rate of hearing loss in patients who had COVID-19 (Can J Neurol Sci. 2022;49:184–195).