Tested positive on On/go at home covid; Tested positive on On/go at home covid; Dose: 01 and Dose: 02 Pfizer BioNtech; Dose: 03 and Dose: 04 Moderna; This is a spontaneous report received from a non-contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 54-year-old male patient received BNT162b2 (BNT162B2), on 21Mar2021 as dose 1, single (Lot number: EN6200) and on 18Apr2021 as dose 2, single (Lot number: EP7534) at the age of 52 years for covid-19 immunisation; elasomeran (COVID-19 VACCINE MODERNA), on 29Oct2021 as dose 3 (booster), single (Lot number: 071F21A) and on 11Jul2022 as dose 4 (booster), single (Lot number: 006M21A) for covid-19 immunisation. The patient's relevant medical history included: "Rheumatoid Arthritis" (unspecified if ongoing). Concomitant medication(s) included: HYDROXYCHLOROQUINE; ADVIL [IBUPROFEN]; DELSYM COUGH + COLD DAY TIME. The following information was reported: INTERCHANGE OF VACCINE PRODUCTS (medically significant) with onset 29Oct2021, outcome "unknown", described as "Dose: 01 and Dose: 02 Pfizer BioNtech; Dose: 03 and Dose: 04 Moderna"; DRUG INEFFECTIVE (medically significant), COVID-19 (medically significant) all with onset 05Dec2022, outcome "not recovered" and all described as "Tested positive on On/go at home covid". The patient underwent the following laboratory tests and procedures: SARS-CoV-2 test: (05Dec2022) Positive, notes: Tested positive on both On/Go covid test and Abbot Binaxnow test on 05Dec2022; (03Dec2022) Negative, notes: Tested negative on 03Dec2022 and 04Dec2022 with at home On/Go covid test; (11Dec2022) Negative, notes: Tested negative again on 11Dec2022 and 12Dec22; (12Dec2022) Negative, notes: Tested negative again on 11Dec2022 and 12Dec22; (04Dec2022) Negative, notes: Tested negative on 03Dec2022 and 04Dec2022 with at home On/Go covid test; (05Dec2022) Positive, notes: Tested positive on both On/Go covid test and Abbot Binaxnow test on 05Dec2022; (10Dec2022) Negative, notes: tested negative on On/Go at home covid test that day; (13Dec2022) Positive, notes: Tested positive on On/go at home covid test 13Dec2022. Therapeutic measures were taken as a result of drug ineffective, covid-19.  Clinical course: Dysgeusia: within an hour of first dose on 05Dec2022 that tasted like persistent burnt plastic. Lasted for the full 5 days. Paxlovid rebound: Covid symptoms of sore throat, fever, cough, fatigue, muscle and joint pain appeared on 03Dec2022. Tested negative on 03Dec2022 and 04Dec2022 with at home On/Go covid test. Tested positive on both On/Go covid test and Abbot Binaxnow test on 05Dec2022, and started Paxlovid evening of 05Dec2022. Compliantly completed full 5 days at 12 hours apart. Last dose was morning of 10Dec2022 and tested negative on On/Go at home covid test that day, Covid symptoms all resolved. Tested negative again on 11Dec2022 and 12Dec2022. Evening of 12Dec2022, covid symptoms returned of scratchy throat, fatigue and cough. Tested positive on On/go at home covid test 13Dec2022 and returned to isolation, symptoms persist. Patient was on other medication in 2 weeks. Patient had not known allergies.  No follow-up attempts are possible. No further information is expected.