Rheumatoid arthritis flare up; swelling and pain in joints/occurs in legs, feet, knees, hips, hands and shoulders.; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) in an adult male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product UPADACITINIB (RINVOQ) for Rheumatoid arthritis.    Concurrent medical conditions included Rheumatoid arthritis.   On 22-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 14-May-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient started UPADACITINIB (RINVOQ) (Oral) at an unspecified dose. On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) (seriousness criterion medically significant) and PERIPHERAL SWELLING (swelling and pain in joints/occurs in legs, feet, knees, hips, hands and shoulders.). At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) had not resolved and PERIPHERAL SWELLING (swelling and pain in joints/occurs in legs, feet, knees, hips, hands and shoulders.) was resolving.            No concomitant medication was provided. Treatment medication was not provided by the reporter.  Patient was still experienced rheumatoid arthritis flare ups in the form of swelling and pain in joints, it lasted about two to three days. Occurs in legs, feet, knees, hips, hands and shoulders.  It was unknown if patient was enrolled in a COVID-19 Vaccine Trial.  The reporter's causality for the event(s) of swollen legs with rinvoq (upadacitinib) was no reasonable possibility. The reporter's causality for the event(s) of experienced rheumatoid arthritis flare ups in the form of swelling and pain in joints/occurs in legs, feet, knees, hips, hands, and shoulders was not provided.  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.  Company comment: This spontaneous case concerns an adult male patient of unknown age with medical history of rheumatoid arthritis, who experienced the unexpected, serious (medically significant) event of rheumatoid arthritis (AESI) an unknown time after the second dose of mRNA-1273. The patient experienced a flare up with pain and swelling in legs, feet, knees, hips, hands, and shoulders. Rheumatoid arthritis can present relapses as part of the natural history of disease, so that could be a contributory factor for the event. Outcome was reported as resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This spontaneous case concerns an adult male patient of unknown age with medical history of rheumatoid arthritis, who experienced the unexpected, serious (medically significant) event of rheumatoid arthritis (AESI) an unknown time after the second dose of mRNA-1273. The patient experienced a flare up with pain and swelling in legs, feet, knees, hips, hands, and shoulders. Rheumatoid arthritis can present relapses as part of the natural history of disease, so that could be a contributory factor for the event. Outcome was reported as resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report.