Seriousness criteria other medically significant. Initial information was received on 11 December 2006 from a literature article. A 25 year old veterinarian received the first two intramuscular injection of 1ml HDCV (Imovax Rabies) for pre exposure immunisation on July 19 and Aug 3, 1987 (Lot number Z0108, expiry date Feb 8, 1998. On Aug 11 she noted weakness in her right leg, followed by clumsiness with her right hand. She had had a brief shaking chill before the onset of symptoms. Neurological examination revealed mild weakness of the right arm, hand, and leg with right arm and patellar Hyperreflexia, and an equivocal plantar extensor response on the right. No cranial nerve, cerebellar, or sensory deficits were detected. A computerized tomographic scan was normal, but a single dose, non delayed contrast CT study revealed a small focus of enhancement near the anterior horn of the left bilateral ventricle, and magnetic resonance imaging indicated increased signal intensity in the periventricular regions bilaterally. Cerebrospinal fluid examination demonstrated: total protein 21.4 mg/dl with four oligoclonal bands, IgG/albumin ratio 0.545 (0.47 in serum), IgG index 1.1 (normal below 0.66), cultures negative for bacteria and fungi, myelin basic protein 1.1 ng/dl (normal). Her serum rabies antibody titer was above 0.5 IU/ml. Evoked responses were normal. Serum protein electrophoresis revealed a polyclonal increase in IgG (1800 mg/dl). Given the strong suspicion of an acute demyelination process, the patient was treated wit intravenous methylprednisone 1g per day for 3 days followed by 2 weeks of prednisone. At the end of the course of prednisone only slight right anterior tibial muscle weakness remained. She remained symptom free for 10 months, after which mild right hemiparesis recurred, proceeded by transient myalgia near the vaccination site. The weakness and right sided Hyperreflexia were identical to those seen in the first episode. MRI revealed several new areas of increased signal intensity in the periventricular regions plus similar lesions in the white matter of the cerebellum. She was again treated with methylprednisone and prednisone, with neat resolution of symptoms. Several months later optic neuritis developed with a Marcus Gunn Pupil, which resolved spontaneously. In this patient an inflammatory demyelinating process affection the central nervous system became symptomatic 8 days after a second dose of HDCV. The enhancing lesion seen on contrast CT suggests a vaccine related inflammation/demyelination rather than multiple sclerosis. Although we cannot be certain that this woman's illness was induced by the HDCV, the systemic manifestation of her illness suggest that this is a reasonable possibility. Follow up information received on 14 February 2007 from an author of the aforementioned literature article. Per the reporter, over subsequent years, the patient follow a clinical course typical of relapsing-remitting multiple sclerosis. The event of demyelination disease of the central nervous system was amended to relapsing-remitting multiple sclerosis based upon this new information. Additional medically relevant information was not provided.