Thoracic Transverse Myelitis; This literature-non-study case was reported in a literature article and describes the occurrence of MYELITIS TRANSVERSE (Thoracic Transverse Myelitis) in a 66-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.       The patient's past medical history included Alcohol use disorder since an unknown date. Concurrent medical conditions included Thoracic aortic aneurysm and Polyneuropathy alcoholic (alcohol-induced peripheral neuropathy).   On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced MYELITIS TRANSVERSE (Thoracic Transverse Myelitis) (seriousness criteria hospitalization and medically significant). The patient was hospitalized for 7 days due to MYELITIS TRANSVERSE. The patient was treated with METHYLPREDNISOLONE (intravenous) for Myelitis transverse, at a dose of UNK UNK, bid. At the time of the report, MYELITIS TRANSVERSE (Thoracic Transverse Myelitis) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Lumbar puncture: showed no abnormalities.. On an unknown date, Magnetic resonance imaging spinal: demonstrated a probable demyelinating process at the T2-T4 levels.   For mRNA-1273 (Spikevax) (Unknown), the reporter considered MYELITIS TRANSVERSE (Thoracic Transverse Myelitis) to be related.    No concomitant medications were reported.  The patient presented with a 3 week history of gait dysfunction and bilateral lower extremity weakness while walking,following the second dose of his COVID-19 vaccination. The patient described his leg symptoms as a "squeezing" heaviness that caused tightness, pain, and weakness with walking, without paresthesias. The patient's onset of bilateral lower extremity weakness and stiffness following a vaccination, accompanied by imaging was suggestive of thoracic spine demyelination.   By day 3 of his hospital stay, the patient started twice daily IV methylprednisolone. By day 4 of his hospital course, the patient's symptoms had improved (normal neurologic exam). By day 7, the patient was discharged home with home health PT.  Company Comment: This literature-non-study case report concerns a 66-year-old male patient with past medical history of alcohol use disorder and alcohol-induced peripheral neuropathy, who experienced serious (due to hospitalization and medical significance) unexpected event of special interest - Myelitis transverse following vaccination with the second dose of the mRNA-1273 vaccine. The exact temporal relationship remained unknown since dates were not provided. Reportedly, the patient presented with a 3 week history of gait dysfunction and bilateral lower extremity weakness while walking. The patient described his leg symptoms as a "squeezing" heaviness that caused tightness, pain, and weakness with walking, without paresthesia. Thoracic spine MRI showed probable demyelinating process at the T2-T4 levels and diagnosis of transverse myelitis was established. The patient was treated with methylprednisolone and his symptoms improved, with normalization of neurologic examination and normal lumbar puncture. The patient was discharged home by day 7. According to the information provided, this patient had past medical history of alcohol use disorder, however, the exact time interval between alcohol use and reported event remained unknown, therefore, history of alcohol use remains a confounder, having in mind that this patient also had documented history of Peripheral neuropathy due to alcohol use. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 08-Dec-2022: Follow up received by safety on 08-Dec-2022 has email with detailed abstract and contains non-significant information. Reporter details added.; Sender's Comments: This literature-non-study case report concerns a 66-year-old male patient with past medical history of alcohol use disorder and alcohol-induced peripheral neuropathy, who experienced serious (due to hospitalization and medical significance) unexpected event of special interest - Myelitis transverse following vaccination with the second dose of the mRNA-1273 vaccine. The exact temporal relationship remained unknown since dates were not provided. Reportedly, the patient presented with a 3 week history of gait dysfunction and bilateral lower extremity weakness while walking. The patient described his leg symptoms as a "squeezing" heaviness that caused tightness, pain, and weakness with walking, without paresthesia. Thoracic spine MRI showed probable demyelinating process at the T2-T4 levels and diagnosis of transverse myelitis was established. The patient was treated with methylprednisolone and his symptoms improved, with normalization of neurologic examination and normal lumbar puncture. The patient was discharged home by day 7. According to the information provided, this patient had past medical history of alcohol use disorder, however, the exact time interval between alcohol use and reported event remained unknown, therefore, history of alcohol use remains a confounder, having in mind that this patient also had documented history of Peripheral neuropathy due to alcohol use. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.