Lost weight; He had no appetite; Stomach cramps; Dehydrated; Tired; no energy; Confused; Headache; Diarrhea; Not digesting food; This is a spontaneous report from a contactable consumer (patient). A 76-years-old male patient received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution injection; Lot Number: EL9269), in left shoulder on 13Feb2021 06:30 as dose 1, single for covid-19 immunisation (76 years old when vaccinated). Medical history included damaged his thumb a couple of years ago. There were no concomitant medications. The patient reported that he got the shot this morning. After he got the shot on 13Feb2021 he had to wait for 15 minutes before he could leave. While waiting the 15 minute time period he got a slight headache at that time. He later stared to drive home and realized he was feeling confused. He decided to get something to eat and that did make him feel better. However, he felt like he was not digesting his food all day. He felt like he was still bloated. He was not processing the food he had eaten. He added, the food he did eat he thought the eggs were not done. Normally, he would not eat them, but he was in a hurry. After that he did not eat any food. He was unable to eat any food. Later that day he began to have a bad reaction. He felt extremely tired. He then started to lose his body fluids. He would sit down and it would run out of him. He decided to quarantine himself. He stated he could not use the internet because he lives in a place where they do not have internet. He was tired, had no energy. He just kept losing body fluids constantly. He has lost weight. He felt dehydrated. Stated he did not have a fever. He had a thermometer and was checking it every hour. It felt like at the time when events first started he was getting worse and worse and so he just laid there. He stated he does not know his current weight. He was dehydrated so bad. He lost so much weight his shoes does not even fit his feet. Later, he confirmed he no longer has a headache. He last had a headache slightly yesterday. He added that the headache could have also occurred due to lack of eating. He had no appetite. He was unable to provide if recovered completely or recovered with lasting effects when probed for outcome. He stated he just felt ran down. He clarified losing body fluids as he had like water, like diarrhea, it was running right out like it would out of a body bag. He could not stop it from coming. It would happen every few minutes. He confirmed that he no longer has diarrhea. He had started taking Kaopectate. He reported that he last had diarrhea a little yesterday morning. He does not have it anymore. He just has no energy left. He would lay down because he was so tired and then he started having the diarrhea and it kept getting worse and worse. He ate a little this morning, a breakfast roll. The day he got the vaccine he was so tired. He slept a lot. This was early afternoon. He got up because he realized he had made a mess with the diarrhea. He started having stomach cramps the night of 13Feb2021. He had some when he laid down. He still had some last night when he laid down. He does not know if the stomach cramps have resolved yet, stated he is still waiting to see. He will have to see when he lies down. However, he is trying to get out and about to get some things done and get something to eat. He stated he was taking Tylenol, but the Tylenol was mainly for the stomach cramps. By 14Feb2021 he started to feel dehydrated. He felt that by then he had already stopped up the sewage system. He was taking electrodes from (Pharmacy) due to the dehydration. He knew this was going to be a problem. Therefore, someone went out and got this for him. He stated that he feels better overall. He will truly see when he tries to get something to eat. He stated he does not take any medications whatsoever on a regular basis. He added, the guy who gave him the shot caller does not believe he has given too many shots before. He thought he was a rookie. He stated he went too high to begin with. He said that normally, shots don't hurt with him and this time it did slightly. He reported that he gets the flu vaccine every year. He was supposed to get the second shot 06Mar2021, but he was not sure about if he should get it and has questions about that. The outcome of the event headache was recovered while diarrhea, he had no appetite, lost weight and confused was not recovered. The outcome of the event not digesting food, dehydrated and stomach cramps was unknown while the outcome of tired; no energy was recovering.  Follow-up (14May2021): Follow-up attempts completed. No further information expected.