Some patients reported a sudden hearing loss after receiving COVID-19 vaccines. Researchers at Johns Hopkins University School of Medicine investigated the cases and published their results in JAMA Otolaryngology-Head & Neck Surgery. Their preliminary conclusions are that the messenger RNA vaccines (mRNA) by Pfizer-BioNTech and Moderna did not cause the hearing loss.

Based on the Vaccine Adverse Events Reporting System (VAERS) data, there were rates of sudden sensorineural hearing loss after COVID-19 vaccinations in 0.3 to 4.1 per 100,000 per year. The American Academy of Otolaryngology-Head and Neck Surgery estimates this type of hearing loss of 5 to 27 per 100,000 annually. There are about 66,000 new cases in the U.S. each year.

“Among the otolaryngology community and larger medical community, there is a lot of interest surrounding a perception of an increased rate of sudden hearing loss that has been observed in some patients after COVID vaccination,” Eric Formeister, a physician at Johns Hopkins and co-author of the study, told MedPage Today.

“However, sudden hearing loss can also occur naturally, so it is not known whether sudden hearing loss occurring after COVID vaccination is coincidental or may be related to the vaccine. Further, some patients who have suffered sudden hearing loss after the first dose have been hesitant to receive the second dose due to safety concerns.”

The published report is a preliminary analysis, so the researchers admit they do not have definitive data yet.

“Unanswered questions include whether providers should still recommend a second vaccination if a patient experiences hearing symptoms after an initial vaccine dose,” said Elliott Kozin, of Massachusetts Eye and Ear in Boston, who was not involved in the study.

“In addition, treatment of sudden sensorineural hearing loss is typically a short course of oral or injected steroids. We do not know if the treatment of sudden sensorineural hearing loss with steroids may decrease the efficacy of concurrent vaccination.”

The study, using VAERS data, identified 147 cases of sudden hearing loss, deafness, deafness unilateral, deafness neurosensory, and hypoacusis (some loss of hearing) associated with COVID-19 vaccinations from December 14, 2020, to March 2, 2021.

Of them, 40 reported hearing loss occurring within about three weeks of vaccination and “high credibility,” meaning a healthcare practitioner had confirmed them with documented hearing tests or steroid treatment. The 40 were classified as “most likely.”

The mean age in the group of 40 was 56 years, and 63% were women. Of them, 12 received the Moderna vaccines and 28 received the Pfizer-BioNTech vaccine. On average, sudden sensorineural hearing loss was reported four days after vaccination. Thirty of the 40 patients received steroids.

In the U.S., 86 million vaccine doses have been administered during that period. Based on the 40 most likely cases, the research estimates a minimum incidence of 0.3 per 100,000 per year, with an assumption of a single dose of vaccine per person. Based on all 147 VAERs reports, the incidence was 4.1 per 100,000 per year.

“These results so far provide evidence that COVID vaccination is not associated with sudden hearing loss,” Formeister said. “One of the pushes behind this publication is to urge clinicians and patients alike to report adverse events to the Vaccine Adverse Events Reporting System, so we may accrue more data to allow a more accurate prediction of the rate of sudden hearing loss after COVID-19 vaccination.”

The study period did not include other vaccines, which in the U.S. would only have been the Johnson & Johnson vaccine.

Sudden sensorineural hearing loss (SSNHL) is defined by The National Institute on Deafness and Other Communications Disorders as “an unexplained, rapid loss of hearing either all at once or over a few days.” SSNHL can be caused by a variety of things, including trauma to the head, infections or some of the drugs used to treat them, some autoimmune diseases, or circulatory problems.

It is reported that nine out of 10 cases never identify the cause of SSNHL. At one time, flu shots were associated with SSNHL, but a 2016 research study in Otolaryngology-Head and Neck Surgery could not place a link.

The authors of the latest study wrote, “We hope these findings will reassure healthcare clinicians and patients to receive all scheduled doses of the vaccination as recommended by current public health guidelines.”