Had four doses since Apr2021; sore arm; tiredness; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team for a Pfizer sponsored program. The reporter is the patient.  A female patient received bnt162b2 (BNT162B2), administered in arm, administration date 06Feb2022 (Lot number: FK9897) as dose 4 (booster), single for covid-19 immunisation. Relevant medical history included: "cancer treatment", start date: 2021 (unspecified if ongoing); "Chemotherapy", start date: 2021 (unspecified if ongoing); "radiation therapy", start date: 2021 (unspecified if ongoing); "Surgery for cancer", start date: 2021 (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (1 Dose, Batch number: EM9810), for COVID-19 Immunization, reaction(s): "tiredness", "In 2021, I had treatments for cancer", "sore arm"; Bnt162b2 (2 Dose, Batch number: ER8729), for COVID-19 Immunization, reaction(s): "tiredness", "In 2021, I had treatments for cancer", "sore arm"; Bnt162b2 (3 Dose, Batch number: EW0181), for COVID-19 Immunization, reaction(s): "tiredness", "In 2021, I had treatments for cancer", "sore arm".  The following information was reported: OFF LABEL USE (non-serious), outcome "unknown", described as "Had four doses since Apr2021"; PAIN IN EXTREMITY (non-serious) with onset Feb2022, outcome "unknown", described as "sore arm"; FATIGUE (non-serious) with onset Feb2022, outcome "unknown", described as "tiredness".  Additional information: She actually wasn't reporting and adverse event. She originally asked a few questions because she get four doses of the COVID vaccine, and all four were Pfizer. She had a great conversation with another agent, and he covered and answered all of her questions. Then, she received this packet of questionnaires. She received one on 09Feb2022, and she has since received 4 different packets on 10Feb2022 and the 11Feb2022. They were all identical on each of these things and her name. She had questions about her vaccines because she had minimal reaction to them. She just had a sore arm and tiredness. She was concerned if she had enough antibodies from the vaccine. Last year in 2021, she was going to cancer treatment and getting chemotherapy when they gave her initial doses of the COVID vaccines. She knew those drugs suppresses the immune system. That was why the medical group wanted her to get her boosters. The medical group online suggested she go in after the 24Jan2022 for her 4th dose of the COVID vaccine so that is what she did. Everyone she knew had reactions after the COVID vaccine, but she only had a little sore arm when she got the vaccines where she got the shots. She had tiredness the first day, and that was it. She was wondering if her body wasn't making antibodies since she didn't have a strong reaction. That was what led to this. All the packets were identical accept their reference numbers: There were three reference numbers. The reference number on the first and the last one are the same. The last one was sent 11Feb2022. She did notice the zip code is wrong on these letters. She only has the lot numbers for her vaccines.   No follow-up attempts are possible. No further information is expected.