Tested positive for Covid; Tested positive for Covid; Get the first vaccine from Moderna, and second one from Moderna and the third one, we get Pfizer.; Booster; Recognized there is some symptoms, that is really weird; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 49 year-old male patient received bnt162b2 (BNT162B2), administered in arm left, administration date 15Dec2021 (Lot number: FDO809) at the age of 49 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "Arthritis" (unspecified if ongoing), notes: Verbatim: Arthritis. There were no concomitant medications. Vaccination history included: Moderna covid-19 vaccine (Dose:1), administration date: 21Apr2021, when the patient was 48 years old, for COVID-19 immunization; Moderna covid-19 vaccine (Dose:2), administration date: 02May2021, when the patient was 48 years old, for COVID-19 immunization. The following information was reported: DRUG INEFFECTIVE (medically significant), COVID-19 (medically significant) all with onset 18Dec2021, outcome "unknown" and all described as "Tested positive for Covid"; INTERCHANGE OF VACCINE PRODUCTS (medically significant) with onset 15Dec2021, outcome "unknown", described as "Get the first vaccine from Moderna, and second one from Moderna and the third one, we get Pfizer."; IMMUNISATION (medically significant) with onset 15Dec2021, outcome "unknown", described as "Booster"; FEELING ABNORMAL (non-serious) with onset Dec2021, outcome "unknown", described as "Recognized there is some symptoms, that is really weird". The patient underwent the following laboratory tests and procedures: sars-cov-2 test: (15Dec2021) negative; (18Dec2021) positive. This is the parent case of the 2 cases. Consumer stated that they got the first vaccine from Moderna, and second one from Moderna and the third one, they got Pfizer. So, they got the Pfizer, the booster one on the 15Dec2021. But after that they recognized there were some symptoms that were really weird. They felt it was from the Pfizer But after that they brought the home test kit and tested, it was positive. They went to bring the kit and the test was positive. So, they need to know what was the side effect because they got the vaccine on the 15Dec2021 and they got infected on the 18Dec2021, that was in only 5 days. The issue was when they got the (Pfizer Covid-19 Vaccine Booster) Booster one on the 15Dec2021. The patient was not taking any medications for arthritis. Consumer stated that it was before back seven days ago, they were in party. But there was not any symptoms. After that they took the vaccine and they did not have any symptoms. After they took the vaccine someone called them, he said there was someone in the party, who tested positive for Covid. So, they did the test, it was negative. That was after, they took the vaccine and the same day on the 15Dec2021 they took the test and it was negative, both of them. But they said they need to repeat the test because it needed like 5 days to confirm the result. So, they brought home the test kit and tested and it was positive, both of them.  Follow-up attempts are completed. No further information is expected.; Sender's Comments: Linked Report(s) : -PFIZER INC-202101816241 same reporter/drug/event, different patient