developed Guillain Barre; This spontaneous case was reported by a patient and describes the occurrence of GUILLAIN-BARRE SYNDROME (developed Guillain Barre) in a 46-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 059E21A) for COVID-19 prophylaxis.     Previously administered products included for Drug use for unknown indication: Flu shot (Flu shot a year before). Past adverse reactions to the above products included No adverse event with Flu shot. Concurrent medical conditions included Fibromyalgia (Chronic Fibromyalgia when she was in Junior High and it had got worse.), Drug allergy (Clomipramine), Allergy to chemicals (Sulfur), Drug allergy (Savella), Drug allergy (Oxycodone), Drug allergy (Tramadol) and Adhesive tape allergy (Any adhesive tape). Concomitant products included ERENUMAB (AIMOVIG [ERENUMAB]), ALENDRONATE SODIUM (ALENDRONATE), ATORVASTATIN, BACLOFEN, BUPRENORPHINE HYDROCHLORIDE (BELBUCA), SUVOREXANT (BELSOMRA) and CALCIUM CITRATE for an unknown indication.    On 12-Aug-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, the patient experienced GUILLAIN-BARRE SYNDROME (developed Guillain Barre) (seriousness criterion medically significant). At the time of the report, GUILLAIN-BARRE SYNDROME (developed Guillain Barre) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Haematocrit: hematocrit levels was at 3 hematocrit levels was at 3. On an unknown date, Red blood cell count: red blood cell drop down really low red blood cell drop down really low.     mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosing remained unchanged.       It was reported that, patient got one of the vaccines in the left and one in right IM. It was also reported that, it started after she got the first shot. She had not experienced similar events in the past. Patient had not tested positive or was diagnosed with COVID. Patient was taking medications. Company comment: This spontaneous case concerns a 46-year-old female patient, with no relevant medical history, who experienced the serious (due to medically significant) unexpected AESI of GUILLAIN-BARRE SYNDROME after the first dose of mRNA-1273 vaccine. The event was reported with no onset date; hence, exact latency cannot be assessed. The narrative of the source document states that Guillain Barre syndrome progressed to chronic inflammatory demyelinating polyradiculoneuropathy after the second dose of mRNA-1273 vaccine, and she could not stand up or walk alone, she fell constantly and had fractured. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2022-590652.   Most recent FOLLOW-UP information incorporated above includes: On 17-Jun-2022: Follow up document received included: Reporter and patient information, medical history, laboratory tests, concomitant medications and lot number.; Sender's Comments: This spontaneous case concerns a 46-year-old female patient, with no relevant medical history, who experienced the serious (due to medically significant) unexpected AESI of GUILLAIN-BARRE SYNDROME after the first dose of mRNA-1273 vaccine. The event was reported with no onset date; hence, exact latency cannot be assessed. The narrative of the source document states that Guillain Barre syndrome progressed to chronic inflammatory demyelinating polyradiculoneuropathy after the second dose of mRNA-1273 vaccine, and she could not stand up or walk alone, she fell constantly and had fractured. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.