Multiple sclerosis relapse; This literature-non-study case was reported in a literature article and describes the occurrence of MULTIPLE SCLEROSIS RELAPSE (Multiple sclerosis relapse) in a 24-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.   LITERATURE REFERENCE:     The patient's past medical history included Multiple sclerosis (Before receiving the vaccine, patient did not know he had multiple sclerosis). Concurrent medical conditions included Obesity.   On an unknown date, the patient received first dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, received second dose of mRNA-1273 (Spikevax) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced MULTIPLE SCLEROSIS RELAPSE (Multiple sclerosis relapse) (seriousness criterion medically significant). The patient was treated with OCRELIZUMAB at an unspecified dose and frequency. At the time of the report, MULTIPLE SCLEROSIS RELAPSE (Multiple sclerosis relapse) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Angiogram: (Negative) negative for acute intracranial processes and did not show any focal narrowing of the cervical or intracranial arteries.. On an unknown date, Anti-aquaporin-4 antibody: Negative. On an unknown date, Antinuclear antibody: Negative. On an unknown date, Antiphospholipid antibodies: Negative. On an unknown date, CSF cell count: The results of his CSF cell count with differential were all within normal limits.. On an unknown date, CSF immunoglobulin G index: within normal limits. On an unknown date, CSF oligoclonal band: multiple sclerosis panel was positive for seven oligoclonal bands. On an unknown date, Chest X-ray: (Negative) negative for any acute cardiopulmonary disease.. On an unknown date, Contrast echocardiogram: (Positive) positive for a trivial intracardiac shunt.. On an unknown date, Echocardiogram: showed normal left ventricular systolic and diastolic functions.. On an unknown date, Ejection fraction: 55-60 percent. On an unknown date, Electrocardiogram: consistent with sinus rhythm.. On an unknown date, Heart rate: 89 heart beats per minute. On an unknown date, Magnetic resonance imaging head: An ovoid 18 mm subcortical left frontal white matter hyperintense lesion with restricted diffusion and smudge-like contrast enhancement. A round 13 mm T2 FLAIR (fluid-attenuated inversion recovery) signal hyperintense lesion in the left frontal white matter abutting the frontal horn of the left lateral ventricle. This lesion does not have restricted diffusion and lacks contrast enhancement. There was no evidence of involvement below the tentorium cerebelli, and the optic nerves appeared normal.. On an unknown date, Neurological examination: cranial nerves were intact on examination. There was no evidence of facial droop, eyelid lag, and extraocular movement abnormalities. There was no evidence of bowel or bladder symptoms.. On an unknown date, Polymerase chain reaction: Meningitis and encephalitis polymerase chain reaction panel was unremarkable..     For mRNA-1273 (Spikevax) (Unknown), the reporter did not provide any causality assessments.   No concomitant medications were reported.  In this report a case of multiple sclerosis relapse following the Moderna COVID-19 vaccine was reported. The patient was presented to the emergency department for evaluation of right-sided facial weakness, dysarthria, and dizziness two days after receiving first dose of the Moderna COVID-19 vaccine. The patient denied any previous similar presentation, headaches, chest pain, shortness of breath, and abdominal tenderness.   Motor strength was 5/5 bilaterally in both upper and lower extremities, tandem gait was intact, and there were no sensory neurological deficit, dysdiadochokinesia, or abnormal Romberg sign. There was no evidence of facial droop, eyelid lag, and extraocular movement abnormalities. There was no evidence of bowel or bladder symptoms.  Acute flare was treated with intravenous corticosteroids. The patient subsequently underwent a lumbar puncture. Myelin oligodendrocyte glycoprotein was not checked. The patient was diagnosed with multiple sclerosis. Subsequently the patient received the second dose of the Moderna vaccine one month and four days later without further side effects.  The author concluded that many cases of multiple sclerosis relapses have been reported following the administration of COVID-19 vaccines with different mechanisms of action and this case is an example of the novel Moderna SARS-CoV-2 vaccine as a potential trigger of multiple sclerosis relapse. The author suggested further research needs to be done to better comprehend the mechanism of these relapses following the administration of the different COVID-19 vaccines.  Company Comment: This literature-non-study case concerns a male patient aged 24 years with a medical history of obesity and multiple sclerosis (Patient did not know he had multiple sclerosis prior to vaccination) reported, who experienced the unexpected serious (medically significant) AESI event of Multiple sclerosis relapse. Patient presented to the Emergency unit with history of right-sided facial weakness, dysarthria, and dizziness two days after receiving his first dose of the mRNA-1273 vaccine. He denied any previous similar presentation. On examination, Motor strength was 5/5 bilaterally in both upper and lower extremities, tandem gait was intact, and there were no sensory neurological deficit, dysdiadochokinesia, or abnormal Romberg sign. Cranial nerves were intact, no evidence of facial droop, eyelid lag, and extraocular movement abnormalities. No bowel or bladder symptoms. Chest X-ray, electrocardiogram and transthoracic echocardiogram done were normal. A bubble study was positive for a trivial intracardiac shunt. CT angiography of the head and neck was normal. MRI of the brain showed active demyelinating lesion in the left frontal subcortical white matter, additional regions of white matter signal abnormality, involving the left frontal horn, were expected to be older regions of demyelination. Lumbar puncture was done, ruled out Meningitis and encephalitis polymerase chain reaction panel. His multiple sclerosis panel was positive for seven oligoclonal bands. CSF showed normal CSF cell count with differential and immunoglobulin G level. Lupus anticoagulant profile, antinuclear antibodies, and aquaporin-4 antibodies were negative. Myelin oligodendrocyte glycoprotein was not checked. Patient met the diagnostic criteria for definite multiple sclerosis. Based on MRI Brain which showed both older regions of demyelination and new active lesions, relapse of multiple sclerosis was considered. At this point, his acute flare was treated with intravenous corticosteroids and he recovered. He was subsequently started on ocrelizumab. He received the second dose of the Moderna vaccine one month and four days later without further side effects. Relevant medical history of obesity remains as risk factor and multiple sclerosis as confounder to the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This literature-non-study case concerns a male patient aged 24 years with a medical history of obesity and multiple sclerosis (Patient did not know he had multiple sclerosis prior to vaccination) reported, who experienced the unexpected serious (medically significant) AESI event of Multiple sclerosis relapse. Patient presented to the Emergency unit with history of right-sided facial weakness, dysarthria, and dizziness two days after receiving his first dose of the mRNA-1273 vaccine. He denied any previous similar presentation. On examination, Motor strength was 5/5 bilaterally in both upper and lower extremities, tandem gait was intact, and there were no sensory neurological deficit, dysdiadochokinesia, or abnormal Romberg sign. Cranial nerves were intact, no evidence of facial droop, eyelid lag, and extraocular movement abnormalities. No bowel or bladder symptoms. Chest X-ray, electrocardiogram and transthoracic echocardiogram done were normal. A bubble study was positive for a trivial intracardiac shunt. CT angiography of the head and neck was normal. MRI of the brain showed active demyelinating lesion in the left frontal subcortical white matter, additional regions of white matter signal abnormality, involving the left frontal horn, were expected to be older regions of demyelination. Lumbar puncture was done, ruled out Meningitis and encephalitis polymerase chain reaction panel. His multiple sclerosis panel was positive for seven oligoclonal bands. CSF showed normal CSF cell count with differential and immunoglobulin G level. Lupus anticoagulant profile, antinuclear antibodies, and aquaporin-4 antibodies were negative. Myelin oligodendrocyte glycoprotein was not checked. Patient met the diagnostic criteria for definite multiple sclerosis. Based on MRI Brain which showed both older regions of demyelination and new active lesions, relapse of multiple sclerosis was considered. At this point, his acute flare was treated with intravenous corticosteroids and he recovered. He was subsequently started on ocrelizumab. He received the second dose of the Moderna vaccine one month and four days later without further side effects. Relevant medical history of obesity remains as risk factor and multiple sclerosis as confounder to the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.