Rheumatoid arthritis flare up; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) in an adult female patient who received mRNA-1273 (Spikevax) for COVID-19 vaccination.    Co-suspect product included non-company product ADALIMUMAB (HUMIRA) for Rheumatoid arthritis.    Concurrent medical conditions included Rheumatoid arthritis (Moderate to severe).   On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (Intramuscular) 1 dosage form and ADALIMUMAB (HUMIRA) (Subcutaneous) Citrate Free, Solution for injection in pre-filled syringe. On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) (seriousness criterion medically significant). At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) was resolving.        The action taken with mRNA-1273 (Spikevax) (Intramuscular) was unknown.       No concomitant medication was reported. On an unknown date, the patient experienced Rheumatoid arthritis flare up. It was unknown if patient was enrolled in a COVID-19 Vaccine Trial.  Causality for HUMIRA(ADALIMUMAB): The reporter's causality for the event(s) of Rheumatoid arthritis flare up was not provided. No treatment medication was reported.  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, female patient with medical history of Moderate-to-severe Rheumatoid Arthritis treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of rheumatoid arthritis flare-up. The event occurred unknown number of days after receiving Humira and unknown number of days after receiving an unspecified dose of the mRNA-1273 vaccine. Of note, the administration dates of Humira and the mRNA-1273 vaccine were not reported while the event onset date was not provided, hence, the onset latency could not be assessed. It was reported that the patient experienced rheumatoid arthritis flare-up, however, no symptoms were reported. The event was resolving at the time of the report. The medical history of Rheumatoid Arthritis, a chronic inflammatory disorder characterized by flares and remission, remains a confounder. The co-suspect product Humira also remains a confounder. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns an adult, female patient with medical history of Moderate-to-severe Rheumatoid Arthritis treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of rheumatoid arthritis flare-up. The event occurred unknown number of days after receiving Humira and unknown number of days after receiving an unspecified dose of the mRNA-1273 vaccine. Of note, the administration dates of Humira and the mRNA-1273 vaccine were not reported while the event onset date was not provided, hence, the onset latency could not be assessed. It was reported that the patient experienced rheumatoid arthritis flare-up, however, no symptoms were reported. The event was resolving at the time of the report. The medical history of Rheumatoid Arthritis, a chronic inflammatory disorder characterized by flares and remission, remains a confounder. The co-suspect product Humira also remains a confounder. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.