RHEUMATOID ARTHRITIS FLARE UP ON HANDS AND KNEES; INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE; INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE; Interchange of vaccine products; Revaccination with different COVID -19 vaccine; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (RHEUMATOID ARTHRITIS FLARE UP ON HANDS AND KNEES) in an adult male patient who received mRNA-1273 (Spikevax) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect products included non-company products UPADACITINIB (RINVOQ) for Rheumatoid arthritis and TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 vaccination.    There was no reported medical history.    On 20-Mar-2022, the patient received dose of mRNA-1273 (Spikevax) (Intramuscular) 1 dosage form. On an unknown date, the patient started UPADACITINIB (RINVOQ) (Oral) Discontinued and dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) 1 dosage form. On an unknown date, received dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (RHEUMATOID ARTHRITIS FLARE UP ON HANDS AND KNEES) (seriousness criterion medically significant), VACCINATION SITE PAIN (INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE), HEADACHE (INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE), INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID -19 vaccine). At the time of the report, RHEUMATOID ARTHRITIS (RHEUMATOID ARTHRITIS FLARE UP ON HANDS AND KNEES) was resolving, VACCINATION SITE PAIN (INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE) and HEADACHE (INJECTION HURT AND SLIGHT HEADACHE DUE TO VACCINE) had resolved and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID -19 vaccine) outcome was unknown.        The action taken with mRNA-1273 (Spikevax) (Intramuscular) was unknown.       This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in.  Concomitant medications were not reported.  The patient had rheumatoid arthritis flare up on hands and knees due to being off of it to get booster.It was unknown if patient was enrolled in a covid-19 vaccine trial. Treatment medications were not reported.  The reporter's causality for the event(s) of rheumatoid arthritis flare up on hands and knees, injection hurt and slight headache due to vaccine unknown onset and injection hurt and slight headache due to vaccine unknown onset was not provided.  Company comment.  This spontaneous case concerns an adult male patient, in treatment with Upadacitinib for Rheumatoid arthritis, who received Tozinameran COVID  19 vaccine and a dose of mRNA  1273 vaccine (unspecified schedule), and experienced the unexpected, serious medically significant AESI of Rheumatoid arthritis (described as "Rheumatoid Arthritis flare up on hands and knees"). Event onset date was not reported; hence latency and temporal association cannot be properly assessed. The outcome was recovering. No further details were provided for medical reviewing. Revaccination with different COVID  19 vaccine and interchange of vaccine products are considered. Co  suspect products included Tozinameran and Upadacitinib. Flaring of symptoms is part of the natural course of Rheumatoid arthritis. It was reported Upadacitinib was discontinued which may have contributed to "Rheumatoid Arthritis flare up". The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns an adult male patient, in treatment with Upadacitinib for Rheumatoid arthritis, who received Tozinameran COVID  19 vaccine and a dose of mRNA  1273 vaccine (unspecified schedule), and experienced the unexpected, serious medically significant AESI of Rheumatoid arthritis (described as "Rheumatoid Arthritis flare up on hands and knees"). Event onset date was not reported; hence latency and temporal association cannot be properly assessed. The outcome was recovering. No further details were provided for medical reviewing. Revaccination with different COVID  19 vaccine and interchange of vaccine products are considered. Co  suspect products included Tozinameran and Upadacitinib. Flaring of symptoms is part of the natural course of Rheumatoid arthritis. It was reported Upadacitinib was discontinued which may have contributed to "Rheumatoid Arthritis flare up". The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.