This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) in a 30-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 ADALIMUMAB (HUMIRA) for Rheumatoid arthritis. Concurrent medical conditions included Drug allergy and Rheumatoid arthritis. Concomitant products included LEVOTHYROXINE SODIUM (SYNTHROID), AZELASTINE HYDROCHLORIDE (AZELASTINE [AZELASTINE HYDROCHLORIDE]), CETIRIZINE HYDROCHLORIDE (ZYRTEC [CETIRIZINE HYDROCHLORIDE]), MULTIVITAMIN [ASCORBIC ACID; BIOTIN; CALCIUM PANTOTHENATE; CYANOCOBALAMIN; FOLIC ACID; NICOTINIC ACID; PYRIDOXINE HYDROCHLORIDE; RIBOFLAVIN; THIAMINE HYDROCHLORIDE; TOCOPHERYL ACETATE], VITAMIN D3, VACCINIUM SPP. (CRANBERRY [VACCINIUM SPP.]), CURCUMA LONGA (TURMERIC [CURCUMA LONGA]), MAGNESIUM and FISH OIL for an unknown indication. In 2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. In 2021, received first 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) 40 milligram once a week. In 2021, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) (seriousness criterion medically significant), INJECTION SITE BRUISING (INJECTION SITE BRUISING), INJECTION SITE PRURITUS (INJECTION SITE ITCHING), INJECTION SITE ERYTHEMA (INJECTION SITE REDNESS) and INJECTION SITE SWELLING (INJECTION SITE SWELLING). At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up) outcome was unknown and INJECTION SITE BRUISING (INJECTION SITE BRUISING), INJECTION SITE PRURITUS (INJECTION SITE ITCHING), INJECTION SITE ERYTHEMA (INJECTION SITE REDNESS) and INJECTION SITE SWELLING (INJECTION SITE SWELLING) had not resolved. The reporter's causality for the event of injection site redness, injection site swelling, injection site itching, injection site bruising and rheumatoid arthritis symptoms flare after Covid vaccine with Humira was not provided. It was unknown if patient was enrolled in a COVID-19 Vaccine Trial. No treatment information was 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. This spontaneous case concerns a 30-year-old, female patient with medical history of Rheumatoid Arthritis (with Rheumatoid factor, multiple sites without organ or systems involvement) treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of rheumatoid arthritis flare-up, and other unexpected and expected, non-serious events. The events occurred unknown number of days after receiving Humira and unknown number of days after receiving the first dose of the mRNA-1273 vaccine. Of note, the administration date of Humira was not provided and the vaccination dates of the mRNA-1273 vaccine was reported as unspecified dates in 2021 while the event onset dates were reported as unspecified dates in 2021, hence, the onset latency could not be assessed. It was reported that after vaccination, the patient experienced injection site redness, injection site swelling, injection site itching, injection site bruising and rheumatoid arthritis flare-up. Treatment information was not provided. The medical history of Rheumatoid Arthritis, a chronic inflammatory disorder characterized by flares and remission, remains a confounder for the event rheumatoid arthritis flare-up. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. Sender's Comments: This spontaneous case concerns a 30-year-old, female patient with medical history of Rheumatoid Arthritis (with Rheumatoid factor, multiple sites without organ or systems involvement) treated with the co-suspect product Humira (adalimumab), who experienced the unexpected, serious (medically significant) AESI of rheumatoid arthritis flare-up, and other unexpected and expected, non-serious events. The events occurred unknown number of days after receiving Humira and unknown number of days after receiving the first dose of the mRNA-1273 vaccine. Of note, the administration date of Humira was not provided and the vaccination dates of the mRNA-1273 vaccine was reported as unspecified dates in 2021 while the event onset dates were reported as unspecified dates in 2021, hence, the onset latency could not be assessed. It was reported that after vaccination, the patient experienced injection site redness, injection site swelling, injection site itching, injection site bruising and rheumatoid arthritis flare-up. Treatment information was not provided. The medical history of Rheumatoid Arthritis, a chronic inflammatory disorder characterized by flares and remission, remains a confounder for the event rheumatoid arthritis flare-up. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.