she notice boobs were swelling; her boobs are getting bigger; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 28 year-old female patient received bnt162b2 (BNT162B2), administered in arm left, administration date 24May2021 13:00 (Lot number: EW0175) at the age of 28 years as dose 2, single for covid-19 immunisation. The patient's relevant medical history was not reported. There were no concomitant medications. Vaccination history included: Bnt162b2 (Dose: 1, first dose on about 14May2021 at 1200 in the left arm), administration date: 14May2021, when the patient was 28 years old, for Covid-19 immunization. The following information was reported: BREAST SWELLING (non-serious) with onset Jul2021, outcome "not recovered", described as "she notice boobs were swelling"; BREAST ENLARGEMENT (non-serious) with onset Jul2021, outcome "not recovered", described as "her boobs are getting bigger". Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were not taken as a result of breast swelling, breast enlargement.  Additional information: The patient was reporting a side effect with the Pfizer-BioNTech COVID-19 Vaccine. She had the first dose on May but she lost her card, and is not sure what exact date. She said that she was fine, and had no AE after second dose. But mid-Jul, she noticed boobs were swelling and was getting larger. She definitely had to buy a new bra, She noticed this mainly this month as she had gone up 2 sizes. She is a little bit concerned and wanted to know if this has been reported before. The patient reported when she got it, it was fine; she had no problems and no adverse events; until she noticed that her chest size is bigger, her boobs have gone up two sizes. She was asking has that been reported? and has anyone else had this?   She mentioned she was getting a new job and will have new insurance so she doesn't have a primary care physician at this time. The patient reported about first dose she lost her first vaccination card so she is unsure of the exact date and doesn't know the lot; does have a new vaccination card for the second dose that says 24May2021 at 1300 in the left arm; lot EW0175. No NDC, expiration date or dose; mentions there is a number written in #. Adds she lost her first vaccine card and they wrote the information in for her. Also Mentioned she has been drinking high calorie Boost but it is like her body is the same size but her boobs are bigger, like heavy, she never had big boobs ever and this is weird. She noticed mid Jul2021 that her boobs seemed bigger; and then in Aug2021 she was still drinking the high calorie Boost but she had to buy a new bra. It was obvious her boobs were getting bigger. Adds she had just bought a new bra in May2021 and she didn't expect to have to get another on in Aug2021. Finally, she heard someone else said the same thing and she saw it online. Adds in Aug2021 it was obvious; they are bigger; slapping her chest as she is going up and down the stairs. Caller states she has not seen a doctor or gone to the emergency room and has had no treatment. Concomitant Products: States she takes no medications.  No additional Vaccines were administered on same date of the Pfizer Suspect.  AE(s) did not required a visit to Emergency Room or Physician Office. No prior Vaccinations (within 4 weeks) were given. There were no AE(s) following prior vaccinations.There was no medical history (including any illness at time of vaccination). Family Medical History Relevant to AE(s): none. There were no relevant tests done.  No follow-up attempts are possible. No further information is expected.