Information has been received from an investigator concerning the following report: a 1 year old female with a normal birth history (36 weeks EGA) and development, with no concurrent conditions or medical or family history, who entered a study. On 15-MAR-2013, the patient was placed on blinded study therapy with MK-V221 or placebo, subcutaneously. The patient did not receive any prior medication or concomitant therapy. The patient's previous vaccinations included: PENTACEL on 04-MAY-2012, 29-JUN-2012 and 12-SEP-2012; Hepatitis B vaccine (manufacturer unknown) on 29-FEB-2012, 04-MAY-2012, and 12-SEP-2012; INFLUENZA (manufacturer unknown) on 12-SEP-2012 and 05-DEC-2012; PREVNAR 13 on 04-MAY-2012, 29-JUN-2012 and 12-SEP-2012; Rotavirus vaccine (manufacturer unknown) on 04-MAY-2012, 29-JUN-2012 and 12-SEP-2012. On 23-MAR-2013, the patient experienced febrile seizure and status epilepticus. At 21:00 hours, the patient had a generalized tonic-clonic seizure and Emergency Medical Service (EMS) was called. The patient was treated with ATIVAN intravenous (IV) x2 doses enroute to the emergency room with twenty minutes of seizure activity prior to arriving. After arrival to the emergency room, the patient was treated with five more doses of ATIVAN and fosphenytoin IV. The patient had a temperature of 101.5 degrees rectally documented in the ER at 21:50 hours. The patient was intubated; however, it was in the esophagus and the patient had to be reintubated with the use of rocuronium. A chest x-ray showed intubation of the esophagus. A repeated chest x-ray showed right mainstem bronchus intubation with opacification of left hemithorax. Laboratory tests showed a normal complete blood count (CBC) and basic metabolic panel (BMP). Arterial blood gases (ABG) showed pH 7.233, pCO2 52.1 mmHg, pO2 62.0 mmHg, bicarbonate 21.6 mmol/L, T.CO2 23 mmol/L, arterial O2 saturation 83% and based excess-blood-6.0 mmol/L. The reporting investigator indicated that the elevation in the patient's carbon dioxide (CO2) with acidosis was related to the initial intubation in the esophagus. A head computed tomography (CT) was normal. A lumbar puncture showed normal cerebrospinal fluid (CSF). Blood cultures and CSF showed no growth. An I-stat chem 8 was normal. The patient was empirically treated with IV vancomycin and ceftriaxone. The patient was transported from the community hospital to the pediatric intensive care unit (PICU) on 23-MAR-2013 at 23:09 hours. The patient was admitted to the PICU on 24-MAR-2013 at 01:00 hours. The patient did very well and was rapidly weaned from the ventilator and extubated. The patient had a normal magnetic resonance imaging (MRI) and normal electroencephalogram (EEG). The patient continued to receive empiric antibiotics in the PICU and was sedated for the MRI. Pediatric neurology was consulted and provided care in the hospital. The neurology department concluded the seizure as a complex febrile seizure. On 25-MAR-2013, the patient was discharged from the hospital on no routine medications. With the final medical diagnosis, DIASTAT was prescribed to use rectally in case of recurrence of fever and febrile seizure. On 22-APR-2013, the mother stated that the patient had done very well since the hospitalization and had not required any medications. The blinded study therapy was discontinued as a result of the events. The reporting investigator stated that the event of febrile seizure with status epilepticus met the additional serious criteria of life threatening. The reporting investigator considered that the event of febrile seizure and status epilepticus was related to blinded therapy. The seizure occurred 9 days after MMRV vaccination was administered. The reporting investigator indicated the fever and febrile seizure occurred consisted with the known risk of fever following the vaccine and in the expected timeframe. Additional information is expected. Patient, Events and Analysis were updated. The record for this patient was unblinded on 13-MAY-2013.