Presentation (CTI)

OBJECTIVES: While limited prior studies found no clear evidence of an association between COVID-19 vaccination and tinnitus, concerns about a potential link remain due to isolated case reports. This study assessed the risk of tinnitus following XBB.1.5 COVID-19 vaccination, administered alone or coadministered with influenza vaccines, using a modified self-controlled case series (SCCS) design.
METHODS: We conducted an SCCS study among individuals aged ≥12 years enrolled at Kaiser Permanente Southern California, with tinnitus events occurring between September 1, 2023, and March 31, 2024. The exposures included Pfizer-BioNTech and Moderna XBB.1.5 COVID-19 vaccines, with or without influenza vaccine coadministration. The primary outcome was first-ever tinnitus (no documented history before September 1, 2023), and the secondary outcome was first-in-1-year tinnitus, identified using ICD-10 code H93.1* in inpatient, emergency department, and outpatient settings. Tinnitus events on the vaccination day were excluded. Risk intervals were pre-specified as 1-14 days and 1-28 days after vaccination. Relative incidences (RI) and 95% confidence intervals (CI) were estimated, adjusting for seasonality by including tinnitus events among non-recipients of XBB.1.5 COVID-19 vaccines and by including calendar month in the SCCS models.
RESULTS: With 13,940 first-ever tinnitus events among recipients of XBB.1.5 COVID-19 vaccines, no increased risk was observed within 1-14 or 1-28 days following vaccination in the overall analyses. The RI was 0.72 (95% CI: 0.61-0.85) for the 14-day risk interval and 0.86 (95% CI: 0.77-0.96) for the 28-day interval. Subgroup analyses by age and influenza vaccine coadministration status also showed no significant increase in RI. Similarly, no significantly elevated RI was found for first-in-1-year tinnitus in the overall analyses, age-specific analyses, or analyses by coadministration with influenza vaccines.
CONCLUSIONS: Our findings suggest no increased tinnitus risk following XBB.1.5 COVID-19 vaccination, either administered alone or coadministered with influenza vaccines. These results provide reassuring evidence of vaccine safety regarding tinnitus risk.