The association between COVID-19 vaccination and idiopathic sudden sensorineural hearing loss, clinical manifestation and outcomes

Purpose: Previous data demonstrated an increased incidence of Idiopathic Sensorineural Hearing Loss (ISSNHL) in 2021 compared to 2019–2020, suggesting an association with the anti-COVID-19 vaccine. We aimed to assess our center’s incidence and compare the clinical manifestations and outcomes of vaccinated vs. unvaccinated patients. Methods: A retrospective chart review of all patients diagnosed with ISSNHL during 2021 was conducted and compared to patients who presented in 2018–2020. Patient demographics, audiometry features, vaccination status, and prognosis were evaluated. Results: Throughout 2021, 51 patients were diagnosed with ISSNHL, compared with 31 during 2020, 38 in 2019, and 41 in 2018, demonstrating a 64%, 34%, and 24% increase, respectively. Among patients who presented in 2021, 13 (25.4%) received the anti-COVID-19 vaccine within 30 days before their presentation, and 4 received it within 96 h. Most presented after receiving the second or third dose. Patient characteristics, audiometry features, and prognosis did not significantly differ between vaccinated and unvaccinated patients. Conclusions : A marked incline was seen in the 2021 ISSNHL incidence at our medical center, of which 25% of cases were within a month post-anti-COVID-19 vaccination. No significant difference was found in clinical manifestations and outcomes between vaccinated and nonvaccinated patients. While other justifications could be sought, an association cannot be ruled out, and further research is needed.