low grade fever/feverish; felt a little tired; a little chilled; didn't have any energy; wake up very sweaty; normal flare up; everything ached; she had a very sore arm; 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.  An 82-year-old female patient received bnt162b2 omi xbb.1.5 (COMIRNATY (2023-2024 FORMULA)), on 27Sep2023 as dose 1, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Covid-19 vaccine (DOSE 7 (BOOSTER), SINGLE, UNKNOWN MANUFACTURER), for COVID-19 immunization; Covid-19 vaccine (DOSE 6 (BOOSTER), SINGLE, UNKNOWN MANUFACTURER), for COVID-19 immunization; Covid-19 vaccine (DOSE 5 (BOOSTER), SINGLE, UNKNOWN MANUFACTURER), for COVID-19 immunization; Covid-19 vaccine (DOSE4 (BOOSTER), SINGLE, UNKNOWN MANUFACTURER), for COVID-19 immunization; Covid-19 vaccine (DOSE 3 (BOOSTER), SINGLE, UNKNOWN MANUFACTURER); Covid-19 vaccine (DOSE 2, SINGLE, UNKNOWN MANUFACTURER), for COVID-19 immunization; Covid-19 vaccine (DOSE 1, SINGLE, UNKNOWN MANUFACTURER), administration date: Jan2021, for COVID-19 immunization. The following information was reported: PAIN (non-serious) with onset 28Sep2023, outcome "recovered", described as "everything ached"; CONDITION AGGRAVATED (non-serious) with onset 28Sep2023, outcome "recovered", described as "normal flare up"; PAIN IN EXTREMITY (non-serious) with onset 28Sep2023, outcome "recovered", described as "she had a very sore arm"; PYREXIA (non-serious), outcome "not recovered", described as "low grade fever/feverish"; FATIGUE (non-serious), outcome "unknown", described as "felt a little tired"; FEELING COLD (non-serious), outcome "unknown", described as "a little chilled"; ASTHENIA (non-serious), outcome "unknown", described as "didn't have any energy"; HYPERHIDROSIS (non-serious), outcome "unknown", described as "wake up very sweaty". Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were taken as a result of pyrexia.  Additional information: Caller, female, aged 82, received her Comirnaty 12+ 2023-2024 vaccine on 27Sep2023. The next day was a mess and she had the normal flare up, where everything ached, she had a very sore arm. She just took it easy. Then the day after, it started to clear up and dissipated. She had company over and was staying busy. Several days later she noticed she had a low grade fever.  At baseline she usually is 97 point something degrees Fahrenheit. At first she didn't take her temperature, she just felt a little tired, a little chilled, and feverish, didn't have any energy. Her fever was low grade under 100 degrees Fahrenheit. Then it cleared up a little bit, then this week its quite pronounced. She feels the effects, but its still a low grade fever. She's taking her temperature now and its usually 99 something. She might get up in the middle of the night to take Tylenol, or wake up very sweaty and just not have the energy she might normally have. When tried to clarify if she had a low grade fever, it went away, and then came back this week, and how long it went away for; caller stated she isn't even sure if it ever really went away because she wasn't taking her temperature regularly and she was buy doing things. This most recent shot was her 8th Covid vaccine that she's gotten since Jan2021 and she never had this from any of the other vaccines. The reporter is asking whether it is normal for a low grade fever to last for 3 weeks after getting the new Pfizer Covid vaccine?  The information on the batch/lot number for [BNT162B2 OMI XBB.1.5] has been requested and will be submitted if and when received.