neuromyelitis optica; Partial urinary retention; paresthesia distal; hyporeflexia of the bilateral ankle, patella, and biceps reflexes; upper back pain in between her shoulder blades that radiated to her arms and lower chest.; bilateral upper- and lower-extremity weakness; This literature-non-study case was reported in a literature article and describes the occurrence of NEUROMYELITIS OPTICA SPECTRUM DISORDER (neuromyelitis optica) and URINARY RETENTION (Partial urinary retention) in a 46-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.       Concurrent medical conditions included Vitamin B12 deficiency (The patient was on replacement therapy). Concomitant products included CYANOCOBALAMIN (COBALAMIN) for Vitamin B12 deficiency.    On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced NEUROMYELITIS OPTICA SPECTRUM DISORDER (neuromyelitis optica) (seriousness criteria hospitalization and medically significant), URINARY RETENTION (Partial urinary retention) (seriousness criterion medically significant), PARAESTHESIA (paresthesia distal), HYPOREFLEXIA (hyporeflexia of the bilateral ankle, patella, and biceps reflexes), BACK PAIN (upper back pain in between her shoulder blades that radiated to her arms and lower chest.) and MUSCULAR WEAKNESS (bilateral upper- and lower-extremity weakness). The patient was treated with PREDNISONE for Paresthesia distal, at an unspecified dose and frequency and METHYLPREDNISOLONE (intracavernous) for Neuromyelitis optica, at an unspecified dose and frequency. At the time of the report, NEUROMYELITIS OPTICA SPECTRUM DISORDER (neuromyelitis optica), URINARY RETENTION (Partial urinary retention) and PARAESTHESIA (paresthesia distal) was resolving, HYPOREFLEXIA (hyporeflexia of the bilateral ankle, patella, and biceps reflexes) outcome was unknown and BACK PAIN (upper back pain in between her shoulder blades that radiated to her arms and lower chest.) and MUSCULAR WEAKNESS (bilateral upper- and lower-extremity weakness) had resolved. Possible    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Aldolase: normal (normal) Normal. On an unknown date, Antinuclear antibody: normal (normal) Normal and normal (normal) Normal. On an unknown date, Blood count: normal (normal) normal and normal (normal) Normal. On an unknown date, Blood creatine phosphokinase: normal (normal) Normal. On an unknown date, Blood magnesium: normal (normal) Normal. On an unknown date, Blood phosphorus: normal (normal) Normal. On an unknown date, Blood test: normal (normal) Normal, normal (normal) Normal, normal (normal) Normal, normal (normal) Normal, normal (normal) Normal, normal (normal) Normal and normal (normal) Normal. On an unknown date, Blood thyroid stimulating hormone: normal (normal) Normal. On an unknown date, Borrelia test: normal (normal) Normal, normal (normal) Normal, undetectable igg against borrelia burgdorferi. undetectable IgG against Borrelia burgdorferi. and undetectable igm against borrelia burgdorferi. undetectable IgM against Borrelia burgdorferi.. On an unknown date, C-reactive protein: normal (normal) Normal. On an unknown date, CSF cell count normal: normal (normal) Normal. On an unknown date, Computerised tomogram abdomen: cardiac etiologies of her pain were ruled out cardiac etiologies of her pain were ruled out. On an unknown date, Computerised tomogram pelvis: cardiac etiologies of her pain were ruled out cardiac etiologies of her pain were ruled out. On an unknown date, Computerised tomogram thorax: cardiac etiologies of her pain were ruled out cardiac etiologies of her pain were ruled out. On an unknown date, Double stranded DNA antibody: normal (normal) Normal. On an unknown date, Electrocardiogram: cardiac etiologies of her pain were ruled out (normal) cardiac etiologies of her pain were ruled out. On an unknown date, Glycosylated haemoglobin: normal (normal) Normal. On an unknown date, Magnetic resonance imaging head: normal (normal) Normal and normal (normal) Normal. On an unknown date, Magnetic resonance imaging neck: abnormal (abnormal) increased, nonexpansile intramedullary signal involving the central gray matter at C6-T2 without enhancement, consistent with NMOSD. On an unknown date, Magnetic resonance imaging spinal: normal (normal) Normal. On an unknown date, Metabolic function test: normal (normal) Normal. On an unknown date, Physical examination: abnormal abnormal. On an unknown date, Troponin: cardiac etiologies of her pain were ruled out cardiac etiologies of her pain were ruled out. On an unknown date, Urine analysis: revealed pyuria without bacteria and culture showe revealed pyuria without bacteria and culture showed at least three organisms, consistent with contamination.. On an unknown date, Vitamin B12 (254 pg/ml-1320 pg/ml): low (Low) 245 pg/mL.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered NEUROMYELITIS OPTICA SPECTRUM DISORDER (neuromyelitis optica), URINARY RETENTION (Partial urinary retention), PARAESTHESIA (paresthesia distal), HYPOREFLEXIA (hyporeflexia of the bilateral ankle, patella, and biceps reflexes), BACK PAIN (upper back pain in between her shoulder blades that radiated to her arms and lower chest.) and MUSCULAR WEAKNESS (bilateral upper- and lower-extremity weakness) to be possibly related.    Two days after receiving the first dose of the SARS-CoV-2 mRNA-1273 vaccine, she developed constant, shooting. She was given a muscle relaxant for bilateral upper- and lower-extremity weakness. At baseline, she was able to perform activities of daily living independently and worked as a teacher. She denied any history of trauma, tick bites, or travel. She had decreased sensation to light touch and sharp materials anteriorly from her feet to the T4 vertebra. Sensation to light touch and sharp materials was also diminished posteriorly from feet to T10 vertebra on the left and to the T6 vertebra on the right. Her proximal and distal strength increased to 4/5 in the lower extremities by day 6 of admission. However, urinary retention and decreased sensation persisted posteriorly up to the T4 vertebra. The patient was ultimately discharged to inpatient rehabilitation on a prednisone taper. She was seen outpatient a month later and her bilateral lower-extremity muscle weakness had resolved. There was no weakness in the upper extremities. She had decreased sensation to light touch and sharp materials anteriorly from her feet to the T4 vertebra. Sensation to light touch and sharp materials was also diminished posteriorly from the feet to the T10 vertebra on the left and to the T6 vertebra on the right. There was hyporeflexia of the bilateral ankle, patella, and biceps reflexes. She had poor static and dynamic balance requiring two-people assistance.  This case concerns a 46-year-old female patient, with no relevant medical history who experienced the serious unexpected event of NEUROMYELITIS OPTICA. The event occurred approximately 10 days after receiving the first dose of Spikevax. The rechallenge is not applicable since no information about the second dose has been disclosed. The benefit risk relation of Spikevax is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 28-Oct-2021: Follow up received by safetyon 28-Oct-2021 included an Email and does not contain any new information.; Sender's Comments: This case concerns a 46-year-old female patient, with no relevant medical history who experienced the serious unexpected event of NEUROMYELITIS OPTICA. The event occurred approximately 10 days after receiving the first dose of Spikevax. The rechallenge is not applicable since no information about the second dose has been disclosed. The benefit risk relation of Spikevax is not affected by this report.