Heart stopped; Could not swallow; This is a spontaneous report from a contactable nurse (patient's wife). An 85-year-old male patient received the first dose of the bnt162b2 (PFIZER-BIONTECH COVID-19 MRNA VACCINE), via an unspecified route of administration on 21Jan2021 at a single dose for COVID-19 immunization.  Medical history included blood pressure abnormal (verbatim: blood pressure) from an unknown date and unknown if ongoing, neuropathy from an unknown date and unknown if ongoing, weight issue from an unknown date and unknown if ongoing, diabetes from an unknown date and unknown if ongoing, walker user from an unknown date and unknown if ongoing.  Concomitant medications included insulin aspart (NOVOLOG) taken for diabetes from an unspecified date to an unspecified date; and he was taking a long acting one as well. The patient previously received the influenza vaccine (MANUFACTURER UNKNOWN) for immunization on unknown dates ("had flu shots before with no reactions and everything, nothing before"). On 24Jan2021, the patient's heart stopped (death, medically significant), and could not swallow (medically significant).  The clinical course was reported as follows: The patient's wife stated the patient was taking insulin aspart (NOVOLOG) and he was taking a long acting one as well. The reporter, the patient's wife and a retired registered nurse (RN) stated, her husband (patient) just died and she thought he died from the COVID vaccine (later clarified the reason of death was-heart stopped). The patient had the vaccine on 21Jan2021, which was on a Thursday, and he was fine. On the following Sunday around 1:30 (on 24Jan2021), the patient was feeling a little weak, however, the patient's wife thought maybe his blood sugar was low. The patient's wife checked, and the patient's blood sugar was 91. The patient's wife went to get some yogurt to feed him in order to get his blood sugar up a little; "which was a normal thing for him, it was not that low for him." Then, suddenly, the patient fell, and the patient's wife could not get a pulse or anything. The patient's wife called an unspecified number and she started compressions; however, he was dead. The patient's wife stated the patient just had his heart test, a three hour long one, and it was "perfect three weeks ago." The patient had just gone to the doctor the other day and his blood pressure was "fine and everything." The patient's wife stated that other than his diabetes, "which he had for (sentence incomplete)." Regarding lab tests, the patient's wife stated, "No, he had it before but not in the last two weeks. He was going for one because we just went to the doctor last week and he was going to call yesterday to make the appointment request to get his blood work done. Blood work has been good except his A1C was always high, but other than that everything was good" (as reported). Regarding causality, the patient's wife stated, "I do, because he was fine until about half an hour before he died. He said to me, I feel a little weak today and then I was talking to him that your upper body strength is really good and then I said, we just have to work on your weight a little more because he did have neuropathy. And then, I went out of the room and all of a sudden I just heard him fall and that is when I just went in to check his blood sugar and it was 91 and I got him yogurt and he started eating that and then that was it, he started spitting it out and he said, I could not swallow and that was it, he just died."  The patient's wife further added, "I just wanted other people to know that things like this happen and I am sure it was from that because he was healthy as could be. He was walking with his walker, the day before outside and he felt fine." The clinical outcome of the event, heart stopped, was fatal. The clinical outcome of the event, could not swallow, was unknown. The patient died on 24Jan2021 due to "heart stopped."  An autopsy was not performed.  The batch/lot numbers for the vaccine, PFIZER-BIONTECH COVID-19 MRNA VACCINE, were not provided and will be requested during follow up.; Reported Cause(s) of Death: Heart stopped