His oxygen level went to 74%; could not breathe; After any exertion at all, talking or anything, left him fatigued and unable to breathe properly; Booster; extremely fatigue; sleeping for almost 24 hours; had double vision all the time; Initially he felt heavy headed; droopy eyes/ his eyelids would droop and could not open left eye; stiff neck; he is very sick and almost died; No energy; decreased appetite; weight loss; This is a spontaneous report received from contactable consumer (patient's wife) from medical information team.  A 75 year-old male patient received bnt162b2 (BNT162B2), administered in arm left, administration date 17Nov2021 15:30 (Lot number: FF8841) at the age of 75 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "obese" (unspecified if ongoing). Family history included: "recurring genetic thyroid cancer" (unspecified if ongoing), notes: Family history of thyroid cancer, Diagnosed 5-6 years ago. The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose 2, single, Lot: EN6207, Injected in unknown arm.), administration date: 19Mar2021, when the patient was 75 years old, for COVID-19 Immunization; Bnt162b2 (Dose 1, single, Lot: EN6203, Injected in unknown arm.), administration date: 26Feb2021, when the patient was 75 years old, for COVID-19 Immunization, reaction(s): "he had no problems"; Flu shot (but unsure if it was within 4 weeks.  She does not have a manufacturer.). The following information was reported: IMMUNISATION (hospitalization, medically significant, life threatening) with onset 17Nov2021, outcome "unknown", described as "Booster"; OXYGEN SATURATION DECREASED (hospitalization, medically significant, life threatening) with onset 30Nov2021 19:00, outcome "unknown", described as "His oxygen level went to 74%"; DYSPNOEA (hospitalization, medically significant, life threatening) with onset 30Nov2021, outcome "unknown", described as "could not breathe"; MALAISE (life threatening) with onset 17Nov2021, outcome "unknown", described as "he is very sick and almost died"; DYSPNOEA EXERTIONAL (hospitalization, medically significant, life threatening) with onset 30Nov2021, outcome "unknown", described as "After any exertion at all, talking or anything, left him fatigued and unable to breathe properly"; HEAD DISCOMFORT (non-serious) with onset 17Nov2021 16:00, outcome "not recovered", described as "Initially he felt heavy headed"; EYELID PTOSIS (non-serious) with onset 17Nov2021 16:00, outcome "not recovered", described as "droopy eyes/ his eyelids would droop and could not open left eye"; DIPLOPIA (non-serious) with onset 19Nov2021, outcome "not recovered", described as "had double vision all the time"; MUSCULOSKELETAL STIFFNESS (non-serious) with onset 17Nov2021, outcome "recovering", described as "stiff neck"; FATIGUE (non-serious) with onset 19Nov2021, outcome "recovering", described as "extremely fatigue"; HYPERSOMNIA (non-serious) with onset 19Nov2021, outcome "recovering", described as "sleeping for almost 24 hours"; DECREASED APPETITE (non-serious) with onset Nov2021, outcome "unknown", described as "decreased appetite"; WEIGHT DECREASED (non-serious) with onset Nov2021, outcome "unknown", described as "weight loss"; ASTHENIA (non-serious) with onset 17Nov2021, outcome "not recovered", described as "No energy". The patient was hospitalized for booster, oxygen saturation decreased, dyspnoea, dyspnoea exertional (start date: 30Nov2021). The events "his oxygen level went to 74%", "could not breathe", "he is very sick and almost died", "after any exertion at all, talking or anything, left him fatigued and unable to breathe properly", "initially he felt heavy headed", "droopy eyes/ his eyelids would droop and could not open left eye", "had double vision all the time", "stiff neck", "extremely fatigue", "sleeping for almost 24 hours", "decreased appetite", "weight loss" and "no energy" were evaluated at the emergency room visit.  The patient's clinical course was also reported as follows: The patient received the Pfizer Covid 19 Booster vaccine on 17Nov2021. Initially he felt heavy headed, droopy eyes, had double vision all the time, stiff neck, extremely fatigue, sleeping for almost 24 hours, decreased appetite, weight loss, and unable to drive.  On 30Nov2021, the patient was having the best day ever when his oxygen level turned to crap, he almost died and the reporter was not sure if he will make it through this. Patient's oxygen level went to 74%, he was admitted to the ICU, placed on a ventilator and is currently still in the ICU on the ventilator. According to the reporter, her husband was being treated by specialist, "we assuming it's the vaccine but we don't know." The reporter informed  that the provider was taking care of her husband asked that she reach out to Pfizer to ask if any other reports have been reported. The reporter informed that her husband is in an ICU now with 6 specialists. He had so many doctors. The reporter informed that the patient was very sick and almost died on 17Nov2021. He may not make it out of this. Two weeks ago, he had his booster and about 45 minutes later, had issues. He never had any allergies and with the first shots, he had no problems. About 45 minutes afterwards, he did not feel well and had to sit down. The reporter thought it was a reaction and sent him to an urgent care. He had heavy headedness, droopy eyes, felt weak and could not drive or anything. He had been in the emergency room and an ambulance ride. At the time of the report, patient sees double all the time. He is very weak, cannot breathe, his eyelids would droop and could not open left eye. He had little control over that. After any exertion at all, talking or anything, left him fatigued and unable to breathe properly. He could walk, but if he walked to bathroom and back, he would need to sit and recover from it. The last thing, this is 2 weeks worth, she could not get to regular doctor and first took him to Urgent Care. From there, he went to the withheld Emergency room and a couple days later, paramedics took to withheld emergency room and since then he had paramedics again come and did not take him, but day on unspecified date, he was really bad and the doctors' said if they did not get him there then, he would have died. He could not breathe and oxygen levels went down to 74, and he was not getting enough air. He is now on a ventilator and has six specialists. The heavy headedness, droopy eyes, felt weak and could not drive or anything has persisted and worsened. The stiff neck was maybe a little improvement, but it was hard to tell if it was masked for everything else going on. Patient was on a ventilator and is not breathing on his own, so reporter did not know if the oxygen level was improving. On 30Nov2021, he had the best day since this mess, and then it turned into the absolute worst day and he almost died.  From the time it all started, he had been extremely fatigued and slept almost 24 hours a day in the beginning and had no energy. For the first 10 days, he was nothing. It improved a little bit. At the time of reporting, patient had cardiologist, neurologist, internist, pulmonologists, all working on him. The reporter did not know if patient will survive. It was very, very, very, bad. He has just gone downhill and it was so strange that he was having the best day since all this started, and it turned to crap, and he almost died. He has had CAT scans, MRI's, X-ray, Echocardiograms and they have tested him all along this process and could not find anything to latch onto and finally they said to call Pfizer. The event required emergency room visit. He had one visit to and Urgent care and then visit to withheld Emergency on 19Nov2021.He was tested and could not find an emergency and released. He had a visit to withheld ER, then corrected to withheld ER on 22Nov2021. They did lots of blood work and exam indication was pain and shortness of breath. He was released. He had a chest X-ray that day too. The next ER visit was by paramedics on 30Nov2021 to withheld ER. They noticed oxygen level of 74 and admitted to ICU and placed on Ventilator, where he remains today. The patient underwent the following laboratory tests and procedures: blood test: (22Nov2021) could not find anything to latch onto, notes: has had 40 blood tests; chest x-ray: (22Nov2021) could not find anything to latch onto; computerised tomogram: (22Nov2021) could not find anything to latch onto; echocardiogram: (22Nov2021) could not find anything to latch onto; magnetic resonance imaging: (22Nov2021) could not find anything to latch onto; oxygen saturation: (30Nov2021) 74. Therapeutic measures were taken as a result of oxygen saturation decreased. There were no additional vaccines administered on the same date as the Pfizer suspect.