1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19/this dose would then be his 4th dose; 1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19/this dose would then be his 4th dose; 1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19/this dose would then be his 4th dose; he got the Pfizer BioNTech Covid 19 booster dose 1 week ago; shooting pain in his left arm; anxiety; chest pain; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team.  A 75 year-old male patient received bnt162b2 (BNT162B2), administration date Dec2021 (Batch/Lot number: unknown) as dose 4 (booster), single for covid-19 immunisation. Relevant medical history included: "Anxiety" (ongoing); "Diabetes" (ongoing); "high blood pressure" (ongoing); "Stroke", start date: Feb2021 (unspecified if ongoing); "he was falling down and went to the trauma center with blood everywhere" (unspecified if ongoing); "he has been in the hospital many times" (unspecified if ongoing), notes: has numerous health issues; "he was not eating" (unspecified if ongoing), notes: something happened a couple of days after his 2nd dose. Stated the wife had to monitor his eating. The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose:1, Caller relays his 1st dose and 2nd dose were Pfizer Covid 19), for COVID-19 immunization; Bnt162b2 (Dose: 2, patient for his 2nd dose of the Pfizer Covid 19 vaccine as he ended up having a stroke.), for COVID-19 immunization, reaction(s): "stroke"; Moderna covid 19 (Dose: 3, his 3rd dose he received in the hospital was Moderna Covid 19.), for COVID-19 immunization. The following information was reported: OFF LABEL USE (non-serious), INTERCHANGE OF VACCINE PRODUCTS (non-serious), outcome "unknown" and all described as "1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19/this dose would then be his 4th dose"; INCORRECT DOSE ADMINISTERED (non-serious) with onset Dec2021, outcome "unknown", described as "1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19/this dose would then be his 4th dose"; IMMUNISATION (non-serious) with onset Dec2021, outcome "unknown", described as "he got the Pfizer BioNTech Covid 19 booster dose 1 week ago"; PAIN IN EXTREMITY (non-serious) with onset Dec2021, outcome "unknown", described as "shooting pain in his left arm"; ANXIETY (non-serious) with onset Dec2021, outcome "unknown", described as "anxiety"; CHEST PAIN (non-serious) with onset Dec2021, outcome "unknown", described as "chest pain".  Additional information: It was reported that the patient had "anxiety and chest pain", and "shooting" pain in his left arm; clarified that this was not pain at the injection site. The wife of patient suspected the anxiety would be due to an upcoming travel. The wife reported the patient's symptoms started recently, they did not happen within 3 days of the vaccine and that was why she did not think it was the vaccine, she thought it was anxiety with traveling. The wife reported she told the patient to take a Xanax. It was informed to the wife that she was not able to give medical advice and to contact his healthcare provider. The caller stated she spoke with both the patient and his wife and felt that the patient was a little older and she did not want to diagnose him with dementia but felt contacting his wife would be better as she was his care taker. The caller stated that the patient got a 3rd vaccine of Covid 19 when he was hospitalized. Stated that this dose would then be his 4th dose. Stated that hospital protocol back in Feb2021 if the person did not have a card on them they immunize them and the wife was upset there was a disconnect at the hospital and she had the vaccine card and he was in trauma unit and she was not able to give the card to the right person. Caller stated they found out they gave the patient the 3rd dose they were given information about that dose. Stated the hospital thought it was his 1st dose and it was really his 3rd dose. Caller stated his 1st dose and 2nd dose were Pfizer Covid 19 and his 3rd dose he received in the hospital was Moderna Covid 19. Stated they only knew about it because they were sent an email saying he got it with the date of when he was hospitalized. The event did not result in emergency room or physician office visit. It was unknown if patient took prior vaccinations (within 4 weeks). It was unknown if the patient underwent relevant tests. It was unknown if the patient received additional vaccines administered on same date of the Pfizer suspect. The awareness date was reported as 10Dec2021 around 7:30am.  The lot/batch number is not available despite the follow-up attempts made. Follow-up attempts completed. No further information is expected.