Characteristics of sudden hearing loss after different COVID-19 vaccinations: a systematic review and meta-analysis.

INTRODUCTION: COVID-19 vaccines are essential to prevent complications and reduce the burden of SARS-CoV-2. However, these vaccines showed side effects such as fatigue, pain, fever, and rarely hearing loss. In this review, we aim to summarize studies investigating hearing loss following COVID-19 vaccination and try to find the possible association and risk factors for this hazardous complication. METHODS: We performed a comprehensive search of five electronic databases (PubMed, Scopus, Web of Science, google scholar, Cochrane) from inception until 9 October 2022. We finally included 16 studies after the first and second scans. We used SPSS to analyze the extracted data. RESULTS: A total of 630 patients were identified, with a mean age of 57.3. Of the patients, 328 out of 609 vaccinated patients took the Pfizer-BioNTech BNT162b2 vaccine, while 242 (40%) took the Moderna COVID-19 vaccine. The mean time from vaccination to hearing impairment was 6.2, ranging from a few hours to one month after the last dose. The results found a significant difference between vaccine types in terms of incidence and prognosis of the condition, while they showed that the number of doses prior to the onset had no significance. CONCLUSION: SNHL has been reported in a small number of people who have received the COVID-19 vaccine, but it is unclear at this time whether the vaccine is directly causing this condition. However, the COVID-19 vaccine has been demonstrated to be safe and effective in preventing illness, and the benefits of vaccination are significant compared to any potential risks. PROTOCOL REGISTRATION: The protocol of this study was registered on Prospero CRD42022367180.