The rash began on his back last night and was itchy/rash is "really itchy; a little painful; broke out in a rash/rash spreading to the front of his chest and covering his arms.; received his Pfizer booster dose on 14Sep2021; received his Pfizer booster dose on 14Sep2021; his blood pressure was up.; The initial safety information received was reporting only non-serious adverse drug reactions, Upon receipt of follow-up information on 22Oct2021, this case now contains serious adverse reactions. Information processed together. This is a spontaneous report from a contactable consumer (patient). A 76-year-old male patient received bnt162b2 (COMIRNATY, COVID 19 Vaccine, mRNA), dose 3 intramuscularly, administered in left arm on 14Sep2021 08:00 (Lot Number: FC3181) as dose 3 (booster), single at the age of 76 years old for COVID-19 immunisation. Medical history included ongoing MS (multiple sclerosis) has had since 60 years old; ongoing mitral valve leaking and he needs it repaired or replaced, It has been checked for 8 years and slowly over 8 year period slowly getting worse; detached right macular in right eye from Mar2016 or Apr2016 and ongoing. Weight: 190-192. There were concomitant medications which included blood pressure medication and cholesterol medication. No additional details provided. . Historic vaccine was bnt162b2 dose 1 received intramuscularly administered in left arm on 22Jan2021 07:00 (Lot: EL3302); and dose 2 received intramuscularly administered in left arm on 12Feb2021 07:30 (Lot: EL9264), both as a single dose at the age of 76 years old for COVID-19 immunisation and no reaction on exposure to vaccination. The patient experienced total severe body rash on 26Sep2021. The seriousness of rash was Important medical event. Event rash resulted in physician office visit. On 27Sep2021, broke out in a rash. The rash began on his back last night and was itchy. By this am, the caller reports him waking up scratching the top of his shoulders and the rash had spread up the top of his back. He did go to his general practitioner for evaluation due to the rash spreading to the front of his chest and covering his arms. On 27Sep2021 he began breaking out in a rash covering 2/3 of his body where it looks like measles, it's a rash, and painful. On 14Sep2021 he had a heart cath. The heart cath and covid booster are the only two things that have changed. He had the heart cath as clarified to see if he had any blockages of vessels (no). The rash started small, and it went up her back, core, arms, chest. It started 27Sep2021 afternoon about 4 in the afternoon and it was itching. It was itching back there. When he woke up this morning he was scratching on top of his shoulders and now the rash is covering chest and arms. He stated he can send pictures. He looked online and saw other people had side effects and had a rash. When he went to the doctor his blood pressure was up. They checked it three times and all three times it was up. It was in the 160s/90s all three times. Treatment: Prednisone, he will take like 4 a day, 3 a day, then 2, then 1. Treatment received which included prednisone 7 day pack cleared in about 5 days. The provider was unsure what the rash may be but did prescribe a steroid dose where the patient will take a tapering dose, 4 tonight, then 3, then 2, then 1. The caller denies any change in food or drinks as well as no medication changes. His HCP does plan to follow up on him tomorrow to see how he is doing and if by the end of the treatment regimen prescribed today, if the rash is not improved/resolved they do plan to do lab work. The caller states the rash was really itchy, like you want to rip your skin off and was a little painful, not all but some. Caller describes the rash as looking like measles. Caller does also state that on 22Sep2021, he did have a heart catheterization performed on the left and ride sides of his heart due to a mitral valve leak. The caller will have to go to the Clinic for repair but notes that he does not want to go with this rash. The caller remains very pleasant and states he just wanted to call for information, he was not complaining. He states that he had no trouble with the 1st and 2nd shot. No reaction, no soreness. However with the booster dose, the patient does not having had mild soreness at the shoulder and after that was okay until the rash. Caller stated he does not know if the rash is related to the COVID Booster or not. Investigations: None yet due to rash, will wait to see if Prednisone works and helps. If not will go back for lab work. No prior Vaccinations (within 4 weeks); he has not have the flu shot yet. Test: TEE procedure in 2021 Result: ultra value Not severe, comments: surgery later this your Nov2021 -Dec2021. No specific relevant test for thromboembolic events with thrombocytopenia. The outcome of rash was recovered on 01Oct2021. The outcome of other events was unknown.  No follow-up attempts are needed. No further information is expected.