relapsing remitting multiple sclerosis (MS); worsening paresthesias involving her lower extremities and torso, then bilateral hands; demyelinating disease in the brain parenchyma and spine; lhermitte's and Uhthoff's phenomena; lhermitte's and Uhthoff's phenomena; This serious case was reported in a literature article and described the occurrence of multiple sclerosis in a 28-year-old female patient who received MMR (Measles mumps rubella vaccine) for prophylaxis.   Co-suspect products included DTPa (Diphtheria tetanus acellular pertussis) for prophylaxis and HUMAN PAPILLOMAVIRUS 9-VALENT-VACCINE (GARDASIL-9) for prophylaxis.  Concurrent medical conditions included familial mediterranean fever (diagnosed at age 18), swelling of feet, suppression of acute phase reactants, stomach pain (during childhood) and vitamin d deficiency. Concomitant products included colchicine.  On an unknown date, the patient received Measles mumps rubella vaccine, Diphtheria tetanus acellular pertussis and GARDASIL-9. On an unknown date, 24 hrs after receiving Measles mumps rubella vaccine and Diphtheria tetanus acellular pertussis and an unknown time after receiving GARDASIL-9, the patient experienced multiple sclerosis (Verbatim: relapsing remitting multiple sclerosis (MS)) (serious criteria GSK medically significant), paresthesia aggravated (Verbatim: worsening paresthesias involving her lower extremities and torso, then bilateral hands), demyelination (Verbatim: demyelinating disease in the brain parenchyma and spine) (serious criteria GSK medically significant), lhermitte's sign (Verbatim: lhermitte's and Uhthoff's phenomena) and uhthoff's phenomenon (Verbatim: lhermitte's and Uhthoff's phenomena). The patient was treated with methylprednisolone and ocrelizumab. The outcome of the multiple sclerosis was resolved and the outcome of the paresthesia aggravated, demyelination, lhermitte's sign and uhthoff's phenomenon were not reported.  The reporter considered the multiple sclerosis, paresthesia aggravated, demyelination, lhermitte's sign and uhthoff's phenomenon to be related to Measles mumps rubella vaccine and Diphtheria tetanus acellular pertussis.  The company considered the multiple sclerosis, paresthesia aggravated, demyelination, lhermitte's sign and uhthoff's phenomenon to be related to Measles mumps rubella vaccine and Diphtheria tetanus acellular pertussis.  Additional Information: GSK Receipt Date: 27-Jul-2023  The co-suspect medication included meningococcal vaccine.  A 28-year-old woman] with familial mediterranean fever (FMF) developed acute myelitis following receipt of 4 vaccinations. Her initial FMF diagnosis was at age 18, following an unexplained swollen red foot and concurrent elevated acute phase reactants. In retrospect, she had previously unexplained, episodic stomach aches during childhood, now attributable to FMF. The diagnosis was confirmed by a pathogenic heterozygous mutation of Met694Ile of the MEFV gene. FMF was symptomatically well-controlled with daily prophylactic colchicine 1.5 mg daily. There was no family history of FMF or autoimmune disease. At age 28 years, she received 4 immunizations: Measles-Mumps- Rubella, Tetanus-Diphtheria-acellular Pertussis, meningococcal, and Human Papillomavirus (HPV) [Gardasil-9]. Twenty-four hours afterwards, she developed worsening paresthesias involving her lower extremities and torso, then bilateral hands. Demyelinating disease in the brain parenchyma and spine was identified on 3.0 Tesla magnetic resonance imaging (MRI) with a T2 hyperintense gadolinium-enhancing lesion at the cervical 2-3 level of the spinal cord. In addition, several gadolinium-enhancing and non-enhancing demyelinating lesions of the brain, inclusive of T2-FLAIR hyperintense lesions oriented perpendicularly to the corpus callosum were also seen (not shown). Serum MOG-IgG was negative, rheumatologic studies (ANA, ANCA, dsDNA, ENA panel) were negative, and cerebrospinal fluid analysis was bland without oligoclonal bands. Vitamin D deficiency was noted (serum 25-OH vitamin D level 11.4 ng/dL). A diagnosis of relapsing remitting multiple sclerosis (MS) was made with fulfillment of the 2017 McDonald criteria. Acutely, she received 5 days of intravenous methylprednisolone with near-complete resolution of myelopathic symptoms. She had residual intermittent Lhermitte's and Uhthoff's phenomena manifesting as recrudescence of paresthesias with physical exertion. Ocrelizumab was provided as a first-line DMT (initial dose and threemaintenance dose cycles of 600 mg IV). Colchicine 1.5 mg daily was continued. At 12 months' follow up, a 7-Tesla brain MRI demonstrated supratentorial white matter lesions containing the central vein sign, a few cortical lesions, a posterior fossa lesion, and several areas of leptomeningeal enhancement predominantly demonstrating a linear/spread/fill pattern, with a rare nodular pattern. She remains relapse free from both MS and FMF flares and by repeat MRI of the neuraxis at 28 months after myelitis onset and 21 months afterocrelizumab initiation. In this case, the topography and morphology of the parenchymal lesions, detected in the brain and spinal cord, were highly suggestive of MS. In this case, the precipitant of 4 simultaneous vaccines raises questions of an exogeneous trigger in an at-risk pro-inflammatory state. MRI features of FMF with the few extant biomarkers found features that are typical of MS. Ocrelizumab was efficacious in the patient in extended follow up.  This article is not available for regulatory reporting purpose due to copyright restriction.