pericarditis in covid19; very strong pain in the legs; cold; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory authority-web. regulatory number: it-minisal02-843090. a 26 year-old male patient received bnt162b2 (comirnaty), administration date 25jan2022 (lot number: fn6618) as dose 3 (booster), single for covid-19 immunisation. the patient's relevant medical history and concomitant medications were not reported. vaccination history included: covid-19 vaccine (dose 1, manufacturer unknown), for covid-19 immunisation; covid-19 vaccine (dose 2, manufacturer unknown), for covid-19 immunisation. the following information was reported: pericarditis (hospitalization) with onset 31jan2022, outcome "not recovered", described as "pericarditis in covid19"; pain in extremity (non-serious) with onset 26jan2022, outcome "unknown", described as "very strong pain in the legs"; nasopharyngitis (non-serious) with onset 26jan2022, outcome "unknown", described as "cold". the event "pericarditis in covid19" was evaluated at the emergency room visit. the patient underwent the following laboratory tests and procedures: sars-cov-2 test: (31jan2022) positive. therapeutic measures were taken as a result of pericarditis. clinical source: adverse reaction following third dose with pfizer for the covid19 vaccine carried out on 25jan2022 in faciltiy through direct access of the facility. the day after the third dose: very strong pains in the legs, subsequently a cold and on monday 31jan2022 carried out a molecular swab with a positive result. from tuesday 01feb2022 the patient begins to feel chest pain in the left side, thursday 03feb2022 having the pain increasingly strong and persistent he goes to the emergency department where pericarditis is diagnosed with consequent hospitalization. currently under therapy. reports of the emergency room are attached in which the doctor reports as the diagnosis "pericarditis in sars-cov-2 infection" follow-up attempts are completed. no further information is expected.; sender's comments: linked report(s) : it-pfizer inc-202200332217 same patient/reporter, different dose/events