hearing loss; sensitive to louder sounds; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 59-year-old female patient received bnt162b2 omi xbb.1.5 (COMIRNATY (2023-2024 FORMULA)), on 20Sep2023 as dose 1, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "hypothyroidism" (unspecified if ongoing), notes: hypothyroidism for over 20 years; "obese" (unspecified if ongoing). Concomitant medication(s) included: LEVOTHYROXINE SODIUM taken for hypothyroidism. Vaccination history included: bnt162b2 (DOSE 1, SINGLE), administration date: 27Mar2021, for COVID-19 Immunization; bnt162b2 (DOSE 2, SINGLE), administration date: 17Apr2021, for COVID-19 Immunization, reaction(s): "generalized 'ick' feeling of being unwell"; bnt162b2 (DOSE 3 (BOOSTER), SINGLE), administration date: 14Oct2021, for COVID-19 Immunization; bnt162b2 (DOSE 4 (BOOSTER), SINGLE), administration date: 18Oct2022, for COVID-19 Immunization. The following information was reported: DEAFNESS (medically significant) with onset 03Oct2023, outcome "recovered" (07Oct2023), described as "hearing loss"; HYPERACUSIS (non-serious) with onset Oct2023, outcome "unknown", described as "sensitive to louder sounds". The patient underwent the following laboratory tests and procedures: Acoustic stimulation tests: (11Sep2023) my hearing results were normal. Clinical courses is as follows: The patient received all Covid vaccines. Previously the patient had the Pfizer Covid shots on 27Mar2021, 17Apr2021, 14Oct2021, 18Oct2022, 20Sep2023. The only other side effect she had was after shot #2 (17Apr2021) that gave her a generalized 'ick' feeling of being unwell. The patient was obese and has taken Levothyroxine for hypothyroidism for over 20 years. Other than that Ithe patient has no other prescriptions or conditions. The hearing loss was sudden, on approximately 03Oct2023-07Oct2023. The patient noticed it when she got a phone call and could not decipher what the person was saying. It sounded like teacher voice, the muffled unintelligible sound that told her someone was talking but it sounded so muffled and other worldly, fading in and out. She originally thought it was a bad connection but when she called back the person who called her, it was the same thing. It was the same thing in any conversation or sound. This was very alarming as the patient worked and had just had a comprehensive physical including a complex hearing test on 11Sep2023 for a new job on a ship she was starting on 05Oct2023. For that test, her hearing results were normal and were recorded on the  Medical Form by the clinic performing the exams. If she was unable to make out sounds, she would not be able to work. Thankfully the hearing 'came back' after about 3-4 days of not being able to decipher sounds or conversations. The loss was very sudden; the return of hearing was gradual, although the patient is still sensitive to louder sounds in a way she wasn't before and she hopes that diminishes. The patient has no history of hearing loss.  The information on the batch/lot number for bnt162b2 omi xbb.1.5 has been requested and will be submitted if and when received.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202300333928 same patient, different dose number/events;