3 weeks later he started to have back and knee pain", " 4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis; 3 weeks later he started to have back and knee pain; 4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis; By 8 weeks, he could barely walk due to the pain from inflammation.; 3 weeks later he started to have back and knee pain; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (3 weeks later he started to have back and knee pain", " 4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis) in a male patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    In May 2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (3 weeks later he started to have back and knee pain", " 4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis) (seriousness criterion medically significant), BACK PAIN (3 weeks later he started to have back and knee pain), INFLAMMATION (4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis), GAIT INABILITY (By 8 weeks, he could barely walk due to the pain from inflammation.) and ARTHRALGIA (3 weeks later he started to have back and knee pain). At the time of the report, RHEUMATOID ARTHRITIS (3 weeks later he started to have back and knee pain", " 4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis), BACK PAIN (3 weeks later he started to have back and knee pain), INFLAMMATION (4 weeks after the vaccine, was when inflammation started to get severe/joint inflammation, ankles, knees, and wrist inflammation, and was diagnosed with rheumatoid arthritis), GAIT INABILITY (By 8 weeks, he could barely walk due to the pain from inflammation.) and ARTHRALGIA (3 weeks later he started to have back and knee pain) outcome was unknown.            Concomitant medication information not provided. Immunosuppressive therapy was given as treatment which helped him a lot.He then received the booster dose, and the symptoms started to flare up again. He said he has no history of this, or family history.  Company comment: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  More information has been requested.   This case was linked to MOD-2021-294569 (Patient Link).   Reporter did not allow further contact; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  More information has been requested.