C-reactive protein was high; OFF LABEL USE; Booster; This is a spontaneous report received from contactable reporter(s) (Physician). The reporter is the patient.  A 75-year-old female patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 13Sep2022 as dose 5 (booster), single (Lot number: GS5342) at the age of 75 years, in left arm for covid-19 immunisation. The patient's relevant medical history was not reported. There were no concomitant medications. Vaccination history included: BNT162b2 (DOSE 1, SINGLE, Lot: EN6201, Expiry: Unknown, Site: Injection in most likely the left arm), administration date: 25Feb2021, when the patient was 73-year-old, for COVID-19 Immunization, reaction(s): "sore arm", "little fatigue"; BNT162b2 (DOSE 2, SINGLE, Lot: ER8730, Expiry: Unknown, Site: injection in the Left arm she thinks), administration date: 26Mar2021, when the patient was 73-year-old, for COVID-19 Immunization, reaction(s): "sore arm", "little fatigue"; BNT162b2 (DOSE 3 (BOOSTER), SINGLE , Lot: FC3184, Expiry: Unknown, Site: Injection in the Left arm she thinks), administration date: 30Sep2021, when the patient was 74-year-old, for COVID-19 Immunization, reaction(s): "sore arm", "little fatigue"; BNT162b2 (DOSE 4 (BOOSTER), SINGLE , Lot: FJ5682, Expiry: Unknown, Site: She thinks it was a injection in the left arm.), administration date: 28Feb2022, when the patient was 74-year-old, for COVID-19 Immunization, reaction(s): "sore arm", "little fatigue". The following information was reported: IMMUNISATION (medically significant) with onset 13Sep2022, outcome "unknown", described as "Booster"; OFF LABEL USE (medically significant) with onset 13Sep2022, outcome "unknown"; C-REACTIVE PROTEIN INCREASED (medically significant) with onset 15Sep2022, outcome "unknown", described as "C-reactive protein was high". The patient underwent the following laboratory tests and procedures: C-reactive protein: (14Sep2022) High, notes: Result: 0.9; Unit: Not Provided.  Clinical course: The Patient's medical history and family medical history relevant to adverse event reported as none. Additional Vaccines administered on same date of the Pfizer Suspect reported as None. It was reported that the adverse event not required emergency Room and Physician Office. Other vaccinations within four weeks prior to the first administration date of the suspect vaccine reported as None. It was reported that caller was a retired physician that had the Pfizer booster for the omicron variant. She did labs the next day and her C-reactive protein was high and the level was 0.9 and a normal C-Reactive Protein should be 0.8 or lower. She said that she read on the internet that the Omicron variant vaccine can cause a higher C- Reactive Protein. Caller asked if that was a side effect of the medication. Caller clarified the name of the medication as the Pfizer Covid-19 Bivalent Vaccine. It was reported that they were monitoring for rheumatological disease and she read that her C-Reactive Protein can go up right after the vaccine. Is this from the vaccine. They are monitoring for granulomatosis with polyangiitis.  Normal C-Reactive Protein was 0.8mg/Deciliter or lower.; Sender's Comments: Based on the information provided and plausible temporal association, the causality between suspect drug BNT162B2 and the event c-reactive protein increased cannot be completely excluded. The impact of this report on the benefit-risk profile of the Pfizer product and on the conduct of the study is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, ethics committees. and investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-2021269182 Same patient, different AE, different dose;