Rheumatoid arthritis flare up; Back pain; Neck pain; Pain in the right arm / Sore arm; Nausea; Headache; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) in a 51-year-old female 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 21-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 19-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, UPADACITINIB (RINVOQ) (Oral) dosage was changed to at an unspecified dose, UPADACITINIB (RINVOQ) (Oral) dosage was changed to at an unspecified dose and UPADACITINIB (RINVOQ) (Oral) dosage was changed to at an unspecified dose. In 2021, the patient experienced PAIN IN EXTREMITY (Pain in the right arm / Sore arm), NAUSEA (Nausea) and HEADACHE (Headache). On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) (seriousness criterion medically significant), BACK PAIN (Back pain) and NECK PAIN (Neck pain). In 2021, PAIN IN EXTREMITY (Pain in the right arm / Sore arm), NAUSEA (Nausea) and HEADACHE (Headache) had resolved. At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) outcome was unknown and BACK PAIN (Back pain) and NECK PAIN (Neck pain) had not resolved.            No concomitant product reported by reporter.  Patient continued to have pain in right side of the body. Patient had rheumatoid arthritis flare up in her hands. It was unknown if patient was enrolled in clinical trials. The symptoms of rheumatoid arthritis flare up included pain with the right hip and right shoulder.  Treatment information included muscle relaxers.  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 a 51 year old female patient, with concurrent condition of rheumatoid arthritis, who experienced the unexpected serious (medically significant) AESI of Rheumatoid arthritis (reported as Rheumatoid arthritis flare up), unknown days after receiving the first dose of mRNA-1273 vaccine in the COVID-19 vaccination series. The patient received the second dose as per recommended schedule. No information on detailed clinical course, relevant investigations, treatment and outcome of the event was available in the report. Concurrent condition of rheumatoid arthritis could be confounding for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This spontaneous case concerns a 51 year old female patient, with concurrent condition of rheumatoid arthritis, who experienced the unexpected serious (medically significant) AESI of Rheumatoid arthritis (reported as Rheumatoid arthritis flare up), unknown days after receiving the first dose of mRNA-1273 vaccine in the COVID-19 vaccination series. The patient received the second dose as per recommended schedule. No information on detailed clinical course, relevant investigations, treatment and outcome of the event was available in the report. Concurrent condition of rheumatoid arthritis could be confounding for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.