SARS-CoV-2 mRNA Vaccines Not Tied to Sudden Hearing Loss

By Lisa Rapaport

June 02, 2021

(Reuters Health) - A preliminary analysis of data from the U.S. Centers for Disease Control and Prevention hasn't found an association between the SARS-CoV-2 messenger RNA vaccines and sudden sensorineural hearing loss.

Motivated by some anecdotal reports of post-vaccination hearing loss, the study team examined data from the CDC Vaccine Adverse Events Reporting System (VAERS) for vaccinations administered from December 14, 2020 to March 2, 2021.

Out of more than 86.5 million vaccine doses administered during the study period, the researchers identified 40 cases of sensorineural hearing loss (SSNHL) that appeared "most likely" to be linked to vaccination because they had a temporal association, occurring within three weeks of receipt of SARS-CoV-2 mRNA vaccines, and were reported and documented by a healthcare clinician.

Because VAERS data is unverified, the authors performed a sensitivity analysis and came up with a minimum incidence rate of 0.3 per 100,000 per year, and a maximum incidence of 4.1 per 100,000 per year. That is still lower than the known population incidence of SSNHL, which ranges from roughly 11 to 77 per 100,000 depending on age group, they note in JAMA Otolaryngology-Head & Neck Surgery.

"We know that adverse events are usually underreported relative to the true rate of an event," said lead study author Dr. Eric Formeister, a neurotology fellow at Johns Hopkins University School of Medicine in Baltimore.

"We accounted for this in our study, and even after assuming a huge underreporting bias for this database, the number of cases in the database did not exceed the number of cases of sudden hearing loss that you would expect based on the size of the population and the time period analyzed," Dr. Formeister said by email.

One limitation of the study is that it only includes data on messenger RNA vaccines, not other SARS-CoV-2 vaccines in use, the authors note. However, the results should reassure clinicians and patients about getting all scheduled doses of messenger RNA vaccines that are recommended in public health guidelines, they conclude.

"In concordance with CDC guidelines, one of our takeaway messages is that individuals should continue to receive the second dose of the vaccination to maximize efficacy against COVID-19," Dr. Formeister said.

This preliminary investigation was necessary, however, as a response to anecdotal reports among otolaryngologists about an uptick in the number of patients presenting with sudden sensorineural hearing loss post-vaccination, said Dr. Heather Weinreich of the department of otolaryngology - head and neck surgery at the University of Illinois at Chicago.

"Regardless of vaccination, there is always a baseline risk of hearing loss that happens in the population and to prove the vaccine increases that risk, the authors needed to show that the incidence of hearing loss was greater among the vaccinated than what is normally occurring in the population," Dr. Weinreich, who wasn't involved in the study, said by email.

"At this point, with the data we have, we are not seeing this risk is greater and I am not surprised by it," Dr. Weinreich added.

SOURCE: JAMA Otolaryngology-Head & Neck Surgery, online May 20, 2021.