fatigue/unusual tiredness; shortness of breath; heart palpitations; report relate to possible inflammation of the heart (myocarditis or pericarditis); hyperthyroidism; raised heart rate; racing heart (tachycardia); primary immunization : unknown manufacturer, at least one was non- pfizer vaccine and booster: comirnaty; primary immunization : unknown manufacturer, at least one was non- pfizer vaccine and booster: comirnaty; this is a spontaneous report received from a contactable reporter(s) (consumer or other non-hcp) from the regulatory authority. regulatory number: gb-mhra-webcovid-202202142043339220-mopy0. other case identifier(s): gb-mhra-adr 26603745. a 38-year-old female patient (not pregnant) received bnt162b2 (comirnaty), administration date 15dec2021 (lot number: fko596) as dose 3 (booster), single for covid-19 immunisation. relevant medical history included: "hysterectomy", start date: oct2019 (unspecified if ongoing); "neoplasm" (unspecified if ongoing), notes: recently had treatment for cancer, leukaemia or lymphoma (radiotherapy or chemotherapy); "chemotherapy", start date: dec2019, stop date: jan2020, notes: 3 weeks chemotherapy; "radiotherapy", start date: dec2019, stop date: jan2020, notes: 5 weeks radiotherapy; "brachytherapy", start date: dec2019, stop date: jan2020, notes: 2 sessions of brachytherapy; "cervical cancer", start date: aug2019 (unspecified if ongoing). the patient's concomitant medications were not reported. vaccination history included: covid-19 vaccine (dose 2; manufacturer unknown), for covid-19 immunisation; covid-19 vaccine (dose 1; manufacturer unknown), for covid-19 immunisation. the following information was reported: off label use (hospitalization, medically significant), interchange of vaccine products (hospitalization, medically significant) all with onset 15dec2021, outcome "unknown" and all described as "primary immunization : unknown manufacturer, at least one was non- pfizer vaccine and booster: comirnaty"; hyperthyroidism (hospitalization, medically significant) with onset 20dec2021, outcome "not recovered", described as "hyperthyroidism"; heart rate increased (hospitalization) with onset 20dec2021, outcome "unknown", described as "raised heart rate"; tachycardia (hospitalization) with onset 20dec2021, outcome "unknown", described as "racing heart (tachycardia)"; fatigue (hospitalization), outcome "unknown", described as "fatigue/unusual tiredness"; dyspnoea (hospitalization), outcome "unknown", described as "shortness of breath"; palpitations (hospitalization), outcome "unknown", described as "heart palpitations"; myocarditis (hospitalization), outcome "unknown", described as "report relate to possible inflammation of the heart (myocarditis or pericarditis)". the patient was hospitalized for off label use, interchange of vaccine products, hyperthyroidism, heart rate increased, tachycardia, fatigue, dyspnoea, palpitations, myocarditis (start date: 20dec2021, hospitalization duration: 2 days). the patient underwent the following laboratory tests and procedures: blood test: (unspecified date) unknown results; electrocardiogram: (unspecified date) unknown results; heart rate: (20dec2021) raised heart rate. clinical course: raised heart rate started 20dec2021 and continued to increase and subsequently ended up admitted to hospital and diagnosed hyperthyroidism. patient had not tested positive for covid-19 since having the vaccine. patient was not enrolled in clinical trial. no follow-up attempts are possible. no further information is expected