Hearing loss in left ear; Tinnitus; This literature-study case was reported in a literature article and describes the occurrence of DEAFNESS UNILATERAL (Hearing loss in left ear) in a 54-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Inner ear disorder.   On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced DEAFNESS UNILATERAL (Hearing loss in left ear) (seriousness criterion medically significant) and TINNITUS (Tinnitus). At the time of the report, DEAFNESS UNILATERAL (Hearing loss in left ear) and TINNITUS (Tinnitus) outcome was unknown. Possible      For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered DEAFNESS UNILATERAL (Hearing loss in left ear) and TINNITUS (Tinnitus) to be possibly related.    No relevant concomitant medications were reported.   Days to Onset of Symptoms given 14-21 days.  Most of the patients are still undergoing treatment, which may include oral, IT steroids, and/or antivirals. In all cases magnetic resonance imaging of the internal auditory canals was also ordered. Pre-treatment audiograms, with the PTA and WRS recorded. The extent of hearing recovery and/or symptom resolution is currently unknown.  This case concerns a 54-year-old female patient with relevant medical history of inner ear disease, who experienced serious unexpected event of deafness unilateral. The events occurred between 14 and 21 days after the second dose of Spikevax however, the exact time to onset was not provided. Rechallenge was not applicable since the event occurred after the second dose of Spikevax. The event was considered as related to suspect drug per the reporter's assessment. Patient's medical history of inner ear disease is  a possible confounder. The benefit-risk relationship of drug is not affected by this report. Although patient's medical history confounds causality, causal or contributing role of Spikevax in exacerbation of inner ear disease cannot be excluded.   This case was linked to MOD-2021-337903, MOD-2021-337994, MOD-2021-337995, MOD-2021-337996, MOD-2021-337998, MOD-2021-337999, MOD-2021-338000, MOD-2021-338001, MOD-2021-338002, MOD-2021-338003, MOD-2021-338004, MOD-2021-338005, MOD-2021-338006, MOD-2021-338007, MOD-2021-338008, MOD-2021-338009, MOD-2021-338010 (Patient Link).; Sender's Comments: This case concerns a 54-year-old female patient with relevant medical history of inner ear disease, who experienced serious unexpected event of deafness unilateral. The events occurred between 14 and 21 days after the second dose of Spikevax however, the exact time to onset was not provided. Rechallenge was not applicable since the event occurred after the second dose of Spikevax. The event was considered as related to suspect drug per the reporter's assessment. Patient's medical history of inner ear disease is  a possible confounder. The benefit-risk relationship of drug is not affected by this report. Although patient's medical history confounds causality, causal or contributing role of Spikevax in exacerbation of inner ear disease cannot be excluded.