Initial report received on 01Jun05. Additional information received on 03June05 and 08Jun05. Additional information received on 13Jun05. This subject is a 17 year old male, who was seen in the ER due to dizziness and a possible seizure enrolled in study. The last dose prior to the event was given on 24May05. The subject developed dizziness and had a possible seizure four days post immunization. He also had blurred vision, nausea and vomiting, had difficulty holding his head up and became sleepy. He was seen in an ER that same day. Treatment included two litters of IV fluids and Zofran. A CT scan and EKG were negative. The subject improved and was discharged from the ER that same day. His past medical history is significant for epilepsy and he has been seizure-free for two years. The subject followed up with his pediatrician the next day and is to be seen by a neurologist on 06Jun05 and is scheduled to have an EEG and MRI. The subject recovered from these events and continued the trial. The events of dizziness and possible seizure were reported by the investigator as related to the study vaccine. From additional information received on 03Jun05 from the investigator, it was unclear what had happened. The subject was at work where he developed dizziness, double vision and lethargy. His parents picked him up and later his mother noted broad based gait and therefore took the subject to the ER. No seizure activity was observed. The subject's previous seizure attack was a tonic-clonic generalized seizure in Nov of 2002. The neurologist pending thorough examination, including EEG, evoked the provisional diagnosis of seizure. The investigator's differential diagnosis included non specific viral syndrome pending normal EEG results. From additional information received on 08Jun05 from the investigator, it was reported that the following findings were noted during the investigator's telephone discussion with the neurologist: per initial evaluation by the neurologist, there were some EEG abnormalities in the left hemisphere, possibly indicating acute seizure disorder. Based upon this, the investigator maintains that the adverse event is seizure. From additional information received on 13Jun05 the results from lab tests taken on 28May05 were provided, included a CT scan of the head with no contrast that showed normal results and a EEG that was abnormal and consistent with left hemisphere seizure focus without clinical accompaniment. It was also confirmed that the subject did not receive Recombivax on 24May05 as previously reported. The investigator confirmed that there was no causal relationship of the observed symptoms of dizziness, ataxia, vomiting, diplopia and somnolence to the Trileptal. From additional information received on 16Jun05 from the site it was confirmed that this subject was discontinued from the study. Per request from CBER on 23Jun05, the Adacel IND number 9226 was added to this case. List of additional information received and available in the source file: Specimen inquiry and physician's phone call summary with subject's parent, telephone contact sheets. No results, EEG report, authorization release of information, ER physician records, ER adult nursing flow sheet, nursing progress notes, ECG report.