Rheumatoid arthritis flare up; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) in a 50-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) 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 15-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 15-Feb-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 ADALIMUMAB (HUMIRA) (Subcutaneous) at an unspecified dose. In January 2021, 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) had not resolved.            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.  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 with Humira(adalimumab) was a reasonable possibility.  Company Comment:  This spontaneous case concerns a 50-year-old female patient with relevant medical history of Rheumatoid arthritis on treatment with Adalimumab, who experienced the unexpected, serious  (medically significant) adverse event of special interest Rheumatoid arthritis (reported as Rheumatoid arthritis flare up) in the context of receiving mRNA-1273 vaccine.  Onset latency could not be determined as the exact date of event onset was not provided. Patient experienced Rheumatoid arthritis flare up on an unspecified date during  the same month the first dose of vaccine was administered. Patient received 2 doses of mRNA-1273 vaccine as primary series given 31 days apart.   Relevant medical history of Rheumatoid arthritis could be considered as confounding to the case as Rheumatoid arthritis  itself is known to result in flares. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 50-year-old female patient with relevant medical history of Rheumatoid arthritis on treatment with Adalimumab, who experienced the unexpected, serious  (medically significant) adverse event of special interest Rheumatoid arthritis (reported as Rheumatoid arthritis flare up) in the context of receiving mRNA-1273 vaccine.  Onset latency could not be determined as the exact date of event onset was not provided. Patient experienced Rheumatoid arthritis flare up on an unspecified date during  the same month the first dose of vaccine was administered. Patient received 2 doses of mRNA-1273 vaccine as primary series given 31 days apart.   Relevant medical history of Rheumatoid arthritis could be considered as confounding to the case as Rheumatoid arthritis  itself is known to result in flares. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.