headache; nausea; pain back; knee pain; groin pain; hip discomfort; itchy rash; rash; fever; off label use; interchange of vaccine products; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory agency (ra). regulatory number: gb-mhra-webcovid-202202161136153910-e1w3j (ra). other case identifier(s): gb-mhra-adr 26609712 (ra). a 24 year-old female patient (not pregnant) received bnt162b2 (comirnaty), administration date 14feb2022 (batch/lot number: unknown) at the age of 24 years as dose 3 (booster), single for covid-19 immunisation. relevant medical history included: "suspected covid-19", start date: 06jan2021, stop date: 01feb2021; "anxiety" (unspecified if ongoing). patient was not currently breastfeeding. concomitant medication(s) included: desogestrel; pregabalin taken for anxiety; venlafaxine. vaccination history included: covid-19 vaccine astrazeneca (dose 1), administration date: 07feb2021, for covid-19 immunization; covid-19 vaccine astrazeneca (dose 2), administration date: 14may2021, for covid-19 immunization. the following information was reported: off label use (medically significant) with onset 14feb2022, outcome "unknown", described as "off label use"; interchange of vaccine products (medically significant) with onset 14feb2022, outcome "unknown", described as "interchange of vaccine products"; headache (medically significant) with onset 15feb2022, outcome "not recovered", described as "headache"; nausea (medically significant) with onset 15feb2022, outcome "not recovered", described as "nausea"; rash (medically significant) with onset 14feb2022, outcome "recovering", described as "rash"; pyrexia (medically significant) with onset 14feb2022, outcome "recovering", described as "fever"; back pain (medically significant) with onset 15feb2022, outcome "not recovered", described as "pain back"; arthralgia (medically significant) with onset 15feb2022, outcome "recovering", described as "knee pain"; groin pain (medically significant) with onset 14feb2022, outcome "not recovered", described as "groin pain"; musculoskeletal discomfort (medically significant) with onset 14feb2022, outcome "not recovered", described as "hip discomfort"; rash pruritic (medically significant) with onset 14feb2022, outcome "recovering", described as "itchy rash". the patient underwent the following laboratory tests and procedures: sars-cov-2 test: (06jan2021) yes - positive covid-19 test, notes: yes - positive covid-19 test. therapeutic measures were taken as a result of headache, nausea, rash, pyrexia, back pain, arthralgia, groin pain, musculoskeletal discomfort, rash pruritic. patient used ibuprofen and paracetamol for pain/ fever, cold compress for fever /knee pain, e45 for rash some effect. patient has not tested positive for covid-19 since having the vaccine. patient was not enrolled in clinical trial. no follow-up attempts are possible; information about lot/batch number cannot be obtained. no further information is expected