actually received her 3rd dose of the Pfizer Covid-19 vaccine; actually received her 3rd dose of the Pfizer Covid-19 vaccine; pain at the injection site; arm was hurting/ Sore arm; This is a spontaneous report from consumer or other non-health professional via Pfizer sponsored program, reporting for his daughter (patient).  A 34-year-old female patient received bnt162b2 (COMIRNATY, PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection; Batch/Lot number: unknown, expiry date: not reported) via an unspecified route of administration on 02Aug2021 (age at vaccination was 34 years) as dose 3, single for covid-19 immunization at a pharmacy. The patient medical history and concomitant medications were not reported. Historical vaccine included that the patient had previously received the first dose of bnt162b2 (COMIRNATY, PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection; Batch/Lot number: unknown, expiry date: not reported) via an unspecified route of administration on an unspecified date in Jan2021 as dose 1, single for covid-19 immunization and second dose of bnt162b2 (COMIRNATY, PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection; Batch/Lot number: unknown, expiry date: not reported) via an unspecified route of administration on an unspecified date in Jan2021 as dose 2, single for covid-19 immunization. Consumer calling on behalf of his daughter that she received her booster dose third dose of the Pfizer Covid-19 vaccine yesterday and 12 hours later, her arm was hurting her, and she took 200mg ibuprofen. Then looked at the internet Advil website and freaked out because it said she wasn't supposed to take it and wants to know if that information was true or not. Patient was wondering about the efficacy of the third dose and concerned it will reduce the efficacy. On 02Aug2021, Side effects were just the sore arm that last night when she took the vaccine. The whole purpose of the booster shot was to increase her antibodies. There was a potential of reduction in antibodies. Investigation Assessment was reported as Yes. On an unknown date, patient underwent lab test and procedures which included SARS-CoV-2 test and Results negative for COVID and SARS-CoV-2 Antibody test results reduction. Outcome of the events was not recovered. Description of Product Complaint: Caller on the line to report an adverse event. He called earlier to report that his 34 years old daughter received a third dose of Pfizer vaccine yesterday and there is more details on the other interaction. He was asking for was what the efficacy of the third dose would be if she took 200 mg Ibuprofen 12 hours after that dose. The first interaction is # (further clarification unknown hence captured as initial report). And this call is originally coming from the agent. He did mention to me also that her first and second dose originally were both in Jan2021 and that's why she took the third dose because she read that efficacy starts to vain. Looking for additional information regarding taking Ibuprofen with the Pfizer COVID vaccine. Reporter stated, "My daughter was just getting really upset because she was not supposed to take Ibuprofen. She is so afraid that she had reduced the efficacy of the third booster shot and the whole purpose of the booster shot is to increase her antibodies and everything through the vaccine I mean to the virus and I have talked to couple of medical professionals, and they say there is a potential reduction."  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.