vestibular disorder is exaggerated; has to walk with a walker; he was talking with someone, started to turn his head to the left, and his whole body went to the left/has no balance; has trouble walking; has trouble getting out of bed; it's like he's a different person.  He feels something in his head & it's getting worse.; feels sea sick; Reeceived second dose on 10Feb2021 and third dose 22Aug2021; tired and spent all day in bed; This spontaneous case was reported by a consumer and describes the occurrence of VESTIBULAR DISORDER (vestibular disorder is exaggerated), WALKING AID USER (has to walk with a walker), BALANCE DISORDER (he was talking with someone, started to turn his head to the left, and his whole body went to the left/has no balance), GAIT DISTURBANCE (has trouble walking) and MOBILITY DECREASED (has trouble getting out of bed) in a male patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 039K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 13-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 22-Aug-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced VESTIBULAR DISORDER (vestibular disorder is exaggerated) (seriousness criterion disability), WALKING AID USER (has to walk with a walker) (seriousness criterion disability), BALANCE DISORDER (he was talking with someone, started to turn his head to the left, and his whole body went to the left/has no balance) (seriousness criterion disability), GAIT DISTURBANCE (has trouble walking) (seriousness criterion disability), MOBILITY DECREASED (has trouble getting out of bed) (seriousness criterion disability), FEELING ABNORMAL (it's like he's a different person.  He feels something in his head & it's getting worse.), MALAISE (feels sea sick), INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Reeceived second dose on 10Feb2021 and third dose 22Aug2021) and FATIGUE (tired and spent all day in bed). At the time of the report, VESTIBULAR DISORDER (vestibular disorder is exaggerated), WALKING AID USER (has to walk with a walker), BALANCE DISORDER (he was talking with someone, started to turn his head to the left, and his whole body went to the left/has no balance), GAIT DISTURBANCE (has trouble walking), MOBILITY DECREASED (has trouble getting out of bed), FEELING ABNORMAL (it's like he's a different person.  He feels something in his head & it's getting worse.), MALAISE (feels sea sick), INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Reeceived second dose on 10Feb2021 and third dose 22Aug2021) and FATIGUE (tired and spent all day in bed) outcome was unknown.            No concomitant medications were provided by the reporter. No treatment information was provided by the reporter.  Company comment: Although the onset date of the events were not reported.  Based on the timing of the 3rd dose to date of report, there is evidence of temporal relationship between the reported events and mRNA-1273 administration, hence the causal relationship cannot be excluded. The event of inappropriate schedule is assessed as not applicable   This case was linked to MOD-2021-306464 (Patient Link).; Sender's Comments: Although the onset date of the events were not reported.  Based on the timing of the 3rd dose to date of report, there is evidence of temporal relationship between the reported events and mRNA-1273 administration, hence the causal relationship cannot be excluded. The event of inappropriate schedule is assessed as not applicable