An 82-year-old man with a history of laryngeal cancer status post hemi-laryngectomy 40 years previously, Barrett's esophagus, and stage 3a chronic kidney disease presented in late February to the Emergency Department 4 weeks after receiving the first dose, and 2 days after receiving the second dose of BNT162b2 COVID-19 vaccine reporting inter mittent episodes of slurred speech. His symptoms had been present for a few weeks, occurring in the evenings, often during his dinner. His symptoms would last approximately 15min then resolve spontaneously. He described his symptoms as his tongue "being in the way," associated with a sensation of perioral numbness. He reported no associated vision changes or eyelid droop, no difficulty swallowing, no other motor deficits, no cognitive deficits. In the Emergency Department his physical exam demon strated a hoarse voice, unchanged from baseline, consistent with history of hemi-laryngectomy, and a normal neuro logic exam including no cranial nerve, motor, sensory, or cognitive deficits. CT scan of the head demonstrated age related white matter changes and no evidence of acute intra cranial abnormality. He was discharged with follow up in ENT, Neurology and Primary Care. Outpatient ENT evaluation 1week after initial presentation to the Emergency Department included direct laryngoscopy without new mucosal lesion or mass and MRI without laryngeal tumor. At follow up in primary care in early April he reported ongoing symptoms of slurred speech and difficulty chewing during dinner and a new symptom of trouble spitting when brushing his teeth at night. He continued to deny daytime symptoms and symptoms with earlier meals. Given his per sistent, intermittent bulbar symptoms, present in the eve nings clinical suspicion for myasthenia gravis was high. Acetylcholine receptor antibodies were ordered demon strating markedly elevated Ach receptor binding Ab 11.4 (normal Ach <0.02) receptor modulating Ab 93%(normal 0%-20%) and striational Ab titer 1:245760 (normal and an EMG was performed showing decrement with repeated nerve stimulation confirming the diagnosis of myasthenia gravis. Secondary evaluation for thymoma was negative. Neurology started treatment with pyridostigmine and speech therapy in early May, and the patient noted initial improvement in his speech and swallowing. However, in late May, within 2weeks of starting treatment, he began to develop eyelid droop. In late June he reported return of dif ficulty with meals after a dental extraction. In mid July, while on vacation, he developed significant generalized weakness and was hospitalized for a severe myasthenia gra vis exacerbation treated with IV pyridostigmine, IVIG and steroids. His hospitalization was complicated by aspiration pneumonia, requirement for ventilator support and inability to swallow requiring PEG tube insertion. He recovered and was discharged to a rehabilitation facility where he contin ued to improve clinically Although our patient presented to the Emergency Department 2 days after receiving his second BNT162b2 COVID-19 vaccine, his family noted symptoms a few weeks earlier. This correlates with administration of the first BNT162b2 COVID-19 vaccine dose. New diagnosis myasthenia gravis after the first dose of COVID-19 vac cine has not been reported in the literature to our knowl edge. Additionally, our patient progressed quickly from symptom onset, diagnosis and initiation of treatment to first severe exacerbation. in our patient due to pre-existing voice changes associated with his history of hemi-laryngectomy. Aside from his his tory of laryngeal cancer, our patient had very few medical conditions, but co-morbidities in the elderly, especially car diovascular risk factors, can make diagnosis of myasthenia in this age group difficult; Sender's Comments: Based on the information provided in the narrative, a causal association between the suspect drug and the event cannot be completely excluded. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.