One year on: an updated systematic review of SARS-CoV-2, COVID-19 and audio-vestibular symptoms

The aim was to systematically review the literature to December 2020, in order to provide a timely summary of evidence on SARS-CoV-2, COVID-19 and audio-vestibular symptoms.
The protocol was registered in the International Prospective Register of Systematic Reviews. The methods were developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Risk of bias was assessed using the National Institutes of Heath quality assessment tools.
After rejecting 850 records, 28 case reports/series and 28 cross-sectional studies met the inclusion criteria.
There are multiple reports of hearing loss (e.g. sudden sensorineural), tinnitus and rotatory vertigo in adults having a wide range of COVID-19 symptom severity. The pooled estimate of prevalence based primarily on retrospective recall of symptoms, was 7.6% (CI: 2.5–15.1), 14.8% (CI: 6.3–26.1) and 7.2% (CI: 0.01–26.4), for hearing loss, tinnitus and rotatory vertigo, respectively. However, these could be an over-estimate because it was not always clear that studies report a change in symptom.
There are multiple reports of audio-vestibular symptoms associated with COVID-19. However, there is a dearth of high-quality studies comparing COVID-19 cases and controls.
Prospective Register of Systematic Reviews (PROSPERO); registration number CRD42020227038).