acute inflammatory demyelinating polyneuropathy; This literature-non-study case was reported in a literature article and describes the occurrence of GUILLAIN-BARRE SYNDROME (acute inflammatory demyelinating polyneuropathy) in a 72-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination    Concurrent medical conditions included Breast cancer (status post bilateral mastectomies and hormone replacement therapy (in remission)).    On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced GUILLAIN-BARRE SYNDROME (acute inflammatory demyelinating polyneuropathy) (seriousness criteria hospitalization and medically significant). The patient was treated with IMMUNOGLOBULINS NOS (intravenous) for Adverse event, at a dose of 0.4 mg/kg. At the time of the report, GUILLAIN-BARRE SYNDROME (acute inflammatory demyelinating polyneuropathy) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Lumbar puncture: high-normal protein level High-normal protein level with all other CSF studies being negative.. On an unknown date, Magnetic resonance imaging: negative Negative for any acute process or radicular abnormalities.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered GUILLAIN-BARRE SYNDROME (acute inflammatory demyelinating polyneuropathy) to be related.    Presented with worsening lower extremity weakness that began 48 hours after receiving the second dose of the Moderna COVID vaccine. Patient also endorsed numbness and tingling along with reduced sensation to hands, forearms, waist, and lower extremities. Patient received 5 days of IVIG at a rate of 0.4 mg/kg, with improvement in strength but still endorsed symptoms of diffuse weakness in the lower extremities as well as gait instability.  Patient was then admitted to the Acute Inpatient Rehabilitation Program. Inpatient Rehabilitation Facility. Timely administration of IVIG delayed the progression of AIDP secondary to Moderna COVID vaccine dose -2 and intensive rehabilitation in an acute rehabilitation setting led to improvement in strength and function.  Company comment: This literature non-study case concerns a 72-year-old female patient with no relevant medical history reported, who experienced the unexpected serious (medically significant) event of Acute inflammatory demyelinating polyradiculoneuropathy after mRNA- 1273 Moderna vaccine. The event occurred approximately 2 days after the second dose of mRNA- 1273 vaccine. Clinical manifestations included lower extremity weakness, gait instability, hypoaesthesia and paraesthesia of hands, forearms, waist and lower extremities. MRI spine was negative for any acute process or radicular abnormalities. Cerebrospinal fluid analysis revealed a high-normal protein level with all other CSF studies being negative. Nerve conduction studies were not provided. Treatment with IV Immunoglobulin was given for 5 days. At the time of the report, muscular weakness was recovering. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.; Sender's Comments: This literature non-study case concerns a 72-year-old female patient with no relevant medical history reported, who experienced the unexpected serious (medically significant) event of Acute inflammatory demyelinating polyradiculoneuropathy after mRNA- 1273 Moderna vaccine. The event occurred approximately 2 days after the second dose of mRNA- 1273 vaccine. Clinical manifestations included lower extremity weakness, gait instability, hypoaesthesia and paraesthesia of hands, forearms, waist and lower extremities. MRI spine was negative for any acute process or radicular abnormalities. Cerebrospinal fluid analysis revealed a high-normal protein level with all other CSF studies being negative. Nerve conduction studies were not provided. Treatment with IV Immunoglobulin was given for 5 days. At the time of the report, muscular weakness was recovering. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.