Patient received the vaccine on 3/6/2021. She was found unresponsive at home with fixed gaze to the right on 3/8/2021. Taken to Medical CTR where initial evaluation CVA but STAT MRI -> encephalitis. Transported to another hospital. Pt had encephalitis with possible seizure. I am not sure this is a vaccine related event but I am reporting it.    Patient is a 77 y.o. female with a past medical history of prediabetes, hypertension, HLD, depression, arthritis, fibromyalgia who presents with altered mental status and encephalopathy with likely seizure.   Patient lives with granddaughter and daughter however patient is independent at home.   On 3/8, Patient developed new onset altered mental status associated with "staring off" and not responding to the family as per granddaughter. EMS was called and patient was taken to outside hospital where there was initial concern for stroke. CT head as well as CT angiogram were completed, which did not show significant stenosis. With unclear aspects of exam patient underwent MRI brain without contrast showing flair changes in the parieto-occipital area of the left hemisphere along with the temporal lobe as well as faint restricted diffusion in the same area. In the emergency department at the outside hospital, she was noted to have fixed gaze to the right as well as significant difficulty following commands. She was given Ativan as well as Keppra 1.2 g. Patient was started on vancomycin, ampicillin, acyclovir, doxycycline, as well as dose of dexamethasone. Patient was then transferred to hospital.   Encephalopathy w/ likely seizure event: As per granddaughter patient was at her baseline throughout the weekend and as of 3/8/2021 patient with altered mental status staring off and not responsive to family members along with notable aphasia. Outside hospital completed CT head as well as CT angiogram with no large vessel occlusion. MRI without contrast was completed showing flair changes of the left parieto-occipital lobe as well as the left temporal lobe with mild DWI changes, Initially there was concern for encephalitis with seizures, and patient was provided Ativan, Keppra 1.5 g, ampicillin, vancomycin, doxycycline, acyclovir as well as a dose of dexamethasone. Patient also present with slight fever to 100.2. Of note patient did received a dose of dexamethasone. Patient also presented with slight fever to 100.2. Of note patient did  received first COVID vaccine on Saturday, 3/6/2021. LP notable for elevated WBC (17 in tube 1), neutrophilic predominance, protein 101, glucose 92. Repeat MRI/MRA head the following day showed improving T2 hyperintensities in the left posterior hemisphere, favoring post-ictal changes given improvement but encephalitis cannot be ruled out based on the available data. During her hospitalization, patient was treated with acyclovir (Stopped when HSN was negative) as well as ampicillin, cefepime, and vancomycin (stopped clinical Improvement and LP results). Patient received Keppra 500 mg tice daily throughout her stay. Continuous video EEG for this first two days of her stay revealed LRDA but no seizures. Patient continued to improve throughout her stay and was deemed stable for discharge to home without outpatient therapy on 3/12. She was discharged on Keppra 500mg twice daily and referred to clinic for follow up.