immunology system has been compromised; hepatitis C antibody test reactive, nucleic acid test is nonreactive; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 64-year-old female patient received BNT162b2 (BNT162B2), on 22Oct2021 as dose 3 (booster), single (Lot number: FE3590) at the age of 64 years, in left arm for covid-19 immunisation. The patient had no relevant medical history. Concomitant medication(s) included: FLU VACCINE VII taken for immunisation, on 05Nov2021 as unk unk, single. Vaccination history included: BNT162b2 (DOSE 1, lot EM6204, given in top of left arm ), administration date: 10Mar2021, when the patient was 63-year-old, for COVID-19 Immunization; BNT162b2 (DOSE 2, lot ER8737, given in top of left arm ), administration date: 31Mar2021, when the patient was 63-year-old, for COVID-19 Immunization; Flu vaccine (prior to getting the Pfizer COVID vaccine.), administration date: 2020, for Immunization. The following information was reported: HEPATITIS C VIRUS TEST POSITIVE (non-serious) with onset Mar2022, outcome "unknown", described as "hepatitis C antibody test reactive, nucleic acid test is nonreactive"; IMMUNE SYSTEM DISORDER (non-serious), outcome "unknown", described as "immunology system has been compromised". The events "hepatitis c antibody test reactive, nucleic acid test is nonreactive" and "immunology system has been compromised" required physician office visit. Relevant laboratory tests and procedures are available in the appropriate section.  Additional information: hepatitis C antibody test reactive, nucleic acid test is nonreactive: Has given blood over the past 5 or 6 years about 12 times and just recently went to see physician because caller got rejected in Mar2022 and again in Jan2023 for the hepatitis C antibody test being reactive, but when the nucleic acid test was done, the nucleic acid test is nonreactive. The blood donors do the hep C virus antibody HCV which came back reactive so then did the more rigorous test, the nucleic acid testing HCV NAT, and that test came back nonreactive. Doctor thinks that caller's immunology system has been compromised due to the vaccine because doctor has been testing caller for the last 4 years and the hep C nucleic acid test has been nonreactive. Only thing different in caller's life is the fact that caller got the COVID vaccine and the 3 boosters. Can't give blood now for 6 months, then will have to get blood tested and pass certain tests. First time occurred was in Mar2022, did same tests when caller went to give blood, does the antibody HCV which was reactive, then the nucleic which was nonreactive. Then the next time occurred was in Jan2023, and the same thing happened, blood was rejected, initial test was reactive, then the nucleic was nonreactive. Doctor has been doing the nucleic acid test once a year for the last 4 years and has always been nonreactive. Patient clarified that she has had 5 doses total, confirmed all 5 doses were the Pfizer COVID vaccine. 4th dose on 10Jun2022 (lot FM7553), given in top of left arm. 5th dose on 25Nov2022 (lot: GJ6796), given in top of left arm. Other vaccines the patient took after dose 3 booster:  Fluzone high dose quad 2022-23: Date: 12Oct2022 Manufacturer: Sanofi-Pasteur Lot number: UJ919AB Expiration date: 30Jun2023 and Prevnar 20: Date: 21Oct2022 Manufacturer: Wyeth/Pfizer Lot number: FJ2603 Expiration date: 30Jun2023 at 0.5ml. Other information: the 3rd or subsequent dose was administered because of age. Vaccination Facility Type for 1st, 2nd, and 3rd doses, 4th and 5th doses given at pharmacy.