Audiovestibular adverse events following COVID-19 vaccinations
Authors: Shetty Aishwarya N , Morgan Hannah J , Phuong Linny K , Mallard John , Vlasenko Diana , Pearce Christopher , Crawford Nigel W , Buttery Jim P , Clothier Hazel J 
Published: November 2023

ABSTRACTImportanceEvidence regarding audiovestibular adverse events post COVID-19 vaccination to date has been inconclusive regarding a potential etiological association. This study used a multi-data source approach to assess incidence of these events following COVID-19 vaccination.ObjectiveTo determine if there was an increase in audiovestibular adverse events following COVID-19 vaccination in South-eastern Australia during January 2021 – March 2023.DesignRetrospective observational analysis of spontaneous reports of audiovestibular events to a statewide vaccine safety surveillance service, SAEFVIC, as well as accompanying self-controlled case series (SCCS) analysis using general practice data collected via the POpulation Level Analysis and Reporting (POLAR) tool with permission from Primary Health Networks (PHNs) as the de-identified dataset owners in Victoria and New South Wales.SettingVictoria and New South Wales (NSW), Australia.ParticipantsVictorians who spontaneously reported an audiovestibular-related symptom or diagnosis to SAEFVIC, and people in Victoria and NSW who presented to a POLAR GP registered practice with a new audiovestibular diagnosis.ExposuresCOVID-19 vaccination with adenovirus vector, mRNA or protein-subunit vaccine.Outcomes and MeasuresIn SAEFVIC, audiovestibular events of interest were ascertained through searching key words in the vaccine safety database. Reporting rates were calculated and compared per 100,000 COVID-19 vaccine doses administered and recorded in the Australian Immunisation Register (AIR). Audiovestibular presentations of interest were isolated from the general practice dataset aggregated by POLAR, by searching for relevant SNOMED CT codes. Similarly, relative incidence (RI) was calculated for all COVID-19 vaccine types.ResultsThis study demonstrates an increase in general practice presentations of vertigo following mRNA vaccines (RI= 1.40P<.001), and tinnitus following both the adenovirus vector and mRNA vaccines (RI= 2.25,P<.001 and 1.53,P<.001 respectively). There was no increase in hearing loss following any COVID-19 vaccinations.Conclusions and RelevanceThis is the first study that demonstrates an increase in audiovestibular presentations following COVID-19 vaccination, in particular, vertigo and tinnitus. Healthcare providers and vaccinees should be alert to potential audiovestibular complaints after COVID-19 vaccination. Our analysis highlights the importance of using large real-world datasets to gather reliable evidence for public health decision making.KEY POINTSQuestion:Is there an increase in audiovestibular adverse events after COVID-19 vaccination (adenovirus vector [AstraZeneca’s Vaxzervria® ChadOx1-S], mRNA [Pfizer-BioNTech’s Comirnaty® BNT162b2 and Moderna’s Spikevax®] or protein-subunit [Novavax’s Nuvaxovid®])?Findings:This Australian study using spontaneous surveillance reports and large-scale general practice data, found an increase in incidence related to vertigo following mRNA vaccines (Relative Incidence = 1.40,P<.001), and tinnitus following both adenovirus vector and mRNA vaccines (Relative Incidence = 2.25,P<.001 and 1.53,P<.001 respectively). No increase in hearing loss following vaccination was observed.Meaning:Healthcare providers and vaccinees should be alert to potential audiovestibular complaints following COVID-19 vaccination.