Information has been received from a Physician's Assistant concerning a 54 year old female patient who on 14-JUL-2011 was vaccinated intramuscularly into the left arm with a dose of ZOSTAVAX (Merck) (lot # and dose not reported). The patient reported tingling in the left side of her face and left arm on the afternoon of 14-JUL-2011 but tingling went away by the evening. On 15-JUL-2011, the patient experienced low grade fever, body aches and soreness in her left side of throat and these symptoms lasted until 18-JUL-2011. The patient came into the office for follow-up on 18-JUL-2011 and stated that she was "feeling better". The office told her to try chicken soup and recommended TYLENOL if symptoms persisted. According to the Physician's Assistant, no warmth or induration was reported around injection site from examination on 18-JUL-2011. Follow up information received from the Physician's Assistant indicated that the patient was seen in the office on 26-JUL-2011. The patient had elevated blood pressure of 162/90 mmHg which she did not have before. Patient was also experiencing more tingling in both of her hands, left thigh and in her toes in both feet. Patient was also reporting her tongue was half numb and she was having speech difficulty. In addition the patient had a headache that was a 7/10 on a pain scale. This headache woke her up at 4 AM. The physician assistant stated the lot number that was given to this patient was lot # 670615/0616AA (exp. 26-JUL-2010). The patient was given 0.65 ml in the left upper extremity and the product was given intramuscularly. A throat culture was conducted and there was no bacteria isolated. Blood work was showing an "increased sed rate" and increase C-reactive protein (CRP). The patient's CRP was elevated to 6.18 from 1.73 (no units were provided). The patient was using ALLEGRA, VIVELLE, and VAGIFEM concomitantly at the time of the ZOSTAVAX (Merck) administration. Follow up information received from the Physician's Assistant indicated that the patient went to the physician's office on 28-JUL-2011 and had difficulty walking as and speaking. The patient was sent to the emergency room at the hospital. Follow up information was received from the Physician's Assistant who confirmed that the patient was seen at the office again on 28-JUL-2011, with difficulty walking and speaking. The patient was sent to the emergency room at the hospital with possible GUILLAIN BARRE Syndrome, and underwent evaluation including a planned lumbar puncture (LP). The Physician's Assistant stated that they considered the patient's experience to be life-threatening, that the patient "travels a lot", and also had pre-existing "non-symptomatic monocytosis" (duration not reported), for which the physician was seeking a consultation from another physician specialist (information not reported). Physician's Assistant did not know if the patient had any other history of preceding viral/gastrointestinal symptoms, nor did she know if the patient had recently been out of the country. Additionally, to the reporter's knowledge, the patient did not have a postvaccination rash. Follow up information was received from the Physician's Assistant who reported that the patient was still in the hospital and stated that they not yet decided about submitting the patient's cerebrospinal fluid (CSF) for polymerase chain reaction (PCR) analysis. A lot check has been initiated. Additional information has been requested.