acute pericarditis. burning chest pain that is accentuated by supine and with breathing; acute pericarditis. burning chest pain that is accentuated by supine and with breathing; off label use; interchange of vaccine products (dose 2: spikevax); this is a spontaneous report received from a contactable reporter(s) (physician) from the regulatory authority-web. regulatory number: it-minisal02-845399. a 28 year-old female patient received bnt162b2 (comirnaty), intramuscular, administered in arm left, administration date 20jan2022 17:52 (lot number: fk6304) as dose 3 (booster), 0.3 ml single for covid-19 immunisation; covid-19 vaccine mrna (mrna 1273) (spikevax), administration date 31aug2021 (batch/lot number: unknown) as dose 2, 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. the following information was reported: off label use (medically significant) with onset 20jan2022, outcome "unknown", described as "off label use"; interchange of vaccine products (medically significant) with onset 20jan2022, outcome "unknown", described as "interchange of vaccine products (dose 2: spikevax)"; pericarditis (medically significant), chest pain (medically significant) all with onset 13feb2022, outcome "not recovered" and all described as "acute pericarditis. burning chest pain that is accentuated by supine and with breathing". the patient underwent the following laboratory tests and procedures: electrocardiogram: (14feb2022) results unknown. therapeutic measures were taken as a result of pericarditis and chest pain. reporter comment: acute pericarditis 24 days after vaccine administration. similar episode 1 month after the second dose.; reporter's comments: acute pericarditis 24 days after vaccine administration. similar episode 1 month after the second dose