SPINAL CORD ISSUE; PARKINSON'S DISEASE FLARE-UP; WEAKNESS; Worsening of ongoing condition; difficulty walking; legs felt very heavy; high stepping when he walked; muscle stiffness and weakness; muscle stiffness and weakness; neck and back pain; neck and back pain; This spontaneous case was reported by a patient family member or friend and describes the occurrence of SPINAL CORD DISORDER (SPINAL CORD ISSUE), PARKINSON'S DISEASE (PARKINSON'S DISEASE FLARE-UP) and ASTHENIA (WEAKNESS) in a 75-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect products included non-company products AMANTADINE HYDROCHLORIDE (GOCOVRI) for Dyskinesia and Parkinson's disease and AMANTADINE for Dyskinesia.    The patient's past medical history included Stent placement. Concurrent medical conditions included Dyskinesia, Parkinson's disease, Spondylitis, Back pain, Neck pain, Body height decreased (PREVIOUSLY REPORTED AS 68 INCHES.), Cardiac disorder and Arthritis (Arthritis in the back with back and neck pain). Concomitant products included CETIRIZINE HYDROCHLORIDE (ZYRTEC ALLERGY) and FLUTICASONE PROPIONATE (FLONASE [FLUTICASONE PROPIONATE]) for Allergy, TAMSULOSIN HYDROCHLORIDE (FLOMAX [TAMSULOSIN HYDROCHLORIDE]) for Benign prostatic hyperplasia, MACROGOL 3350 (MIRALAX) for Constipation, MAGNESIUM for Magnesium supplementation, CARBIDOPA, ENTACAPONE, LEVODOPA (STALEVO [CARBIDOPA;ENTACAPONE;LEVODOPA]) and ROPINIROLE for Parkinson's disease, METHYLCELLULOSE (CITRUCEL), VITAMIN B12 [VITAMIN B12 NOS] and MULTIVITAMIN [VITAMINS NOS] for Supplementation therapy, VITAMIN C [ASCORBIC ACID] for Vitamin C supplementation, COLECALCIFEROL (D3 50) for Vitamin D supplementation, PARACETAMOL (TYLENOL), ACETYLSALICYLIC ACID (ASPIRIN LOW), PRAVASTATIN, CLOPIDOGREL and RASAGILINE MESYLATE (AZILECT) for an unknown indication.   On 20-Feb-2020, the patient started AMANTADINE HYDROCHLORIDE (GOCOVRI) (Oral) 137 milligram once a day. On 27-Feb-2020, AMANTADINE HYDROCHLORIDE (GOCOVRI) (Oral) dosage was changed to 274 milligram at bedtime. On 16-Apr-2020, the patient started AMANTADINE (unknown route) 100 mg. On 30-Jun-2020, AMANTADINE HYDROCHLORIDE (GOCOVRI) (Oral) dosage was changed to 68.5 milligram at bedtime. On 20-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 25-Jan-2021, the patient experienced CONDITION AGGRAVATED (Worsening of ongoing condition), GAIT DISTURBANCE (difficulty walking), LIMB DISCOMFORT (legs felt very heavy), TOE WALKING (high stepping when he walked), MUSCULOSKELETAL STIFFNESS (muscle stiffness and weakness), MUSCULAR WEAKNESS (muscle stiffness and weakness), NECK PAIN (neck and back pain) and BACK PAIN (neck and back pain). On 25-Feb-2021, the patient experienced SPINAL CORD DISORDER (SPINAL CORD ISSUE) (seriousness criterion hospitalization), PARKINSON'S DISEASE (PARKINSON'S DISEASE FLARE-UP) (seriousness criterion hospitalization) and ASTHENIA (WEAKNESS) (seriousness criterion hospitalization). The patient was hospitalized from 25-Feb-2021 to 01-Mar-2021 due to ASTHENIA, PARKINSON'S DISEASE and SPINAL CORD DISORDER. On 01-Mar-2021, SPINAL CORD DISORDER (SPINAL CORD ISSUE) and PARKINSON'S DISEASE (PARKINSON'S DISEASE FLARE-UP) had resolved, ASTHENIA (WEAKNESS) had resolved with sequelae. At the time of the report, CONDITION AGGRAVATED (Worsening of ongoing condition), GAIT DISTURBANCE (difficulty walking), LIMB DISCOMFORT (legs felt very heavy), TOE WALKING (high stepping when he walked), MUSCULOSKELETAL STIFFNESS (muscle stiffness and weakness), MUSCULAR WEAKNESS (muscle stiffness and weakness), NECK PAIN (neck and back pain) and BACK PAIN (neck and back pain) had not resolved.            Based on reporter's causality and attribution to amantadine overdose, the events are assessed as unlikely related to mRNA-1273.   This case was linked to MOD-2021-057120 (Patient Link).; Sender's Comments: Based on reporter's causality and attribution to amantadine overdose, the events are assessed as unlikely related to mRNA-1273.