This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Worsening of RA pain at level 6 on 1-10 scale. knee pain & swollen fingers) in a female patient of an unknown age who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below. Co-suspect product included non-company product TOFACITINIB CITRATE (XELJANZ XR) for an unknown indication. Concurrent medical conditions included Drug allergy (Penicillin v potassium (xeljanz XR)) and Rheumatoid arthritis. Concomitant products included FLUOXETINE, FISH OIL, CETIRIZINE HYDROCHLORIDE, PSEUDOEPHEDRINE HYDROCHLORIDE (ZYRTEC-D) and VITAMIN B COMPLEX for an unknown indication. In June 2020, the patient started TOFACITINIB CITRATE (XELJANZ XR) (unknown route) 11 milligram once a day. On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Worsening of RA pain at level 6 on 1-10 scale. knee pain & swollen fingers) (seriousness criterion medically significant), COVID-19 (COVID illness), SPIDER VEIN (Spider vein) and BREAST MASS (Breast nodule while on XELJANZ (Worsening)). At the time of the report, RHEUMATOID ARTHRITIS (Worsening of RA pain at level 6 on 1-10 scale. knee pain & swollen fingers) and BREAST MASS (Breast nodule while on XELJANZ (Worsening)) had not resolved and COVID-19 (COVID illness) and SPIDER VEIN (Spider vein) outcome was unknown. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Pain assessment (1-10): 6 6. The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown. For mRNA-1273 (Spikevax) (Unknown), the reporter did not provide any causality assessments. It was reported that RA pain was worsening at level 6 on 1-10 scale also experienced the knee pain & swollen fingers. Patient had Covid illness, spider veins, and breast nodule while on Xeljanz XR. Reporter consider events were not caused by suspect product (XELJANZ XR). Treatment Medication use information was not provided by reporter. Company Comment: This spontaneous case concerns an adult female patient with a medical history of Rheumatoid arthritis, who experienced the unexpected serious (medically significant) AESI of Rheumatoid arthritis and unexpected non-serious AESI of Covid-19 unspecified days after receiving a dose of mRNA-1273 vaccine. It was reported that RA pain was worsening at level 6 on 1-10 scale also experienced the knee pain & swollen fingers. Patient had Covid illness, spider veins and breast nodule while on Xeljanz. Patients medical history of Rheumatoid arthritis could be confounding for the event Rheumatoid arthritis. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Event seriousness assessed as per medical judgement. Sender's Comments: This spontaneous case concerns an adult female patient with a medical history of Rheumatoid arthritis, who experienced the unexpected serious (medically significant) AESI of Rheumatoid arthritis and unexpected non-serious AESI of Covid-19 unspecified days after receiving a dose of mRNA-1273 vaccine. It was reported that RA pain was worsening at level 6 on 1-10 scale also experienced the knee pain & swollen fingers. Patient had Covid illness, spider veins and breast nodule while on Xeljanz. Patients medical history of Rheumatoid arthritis could be confounding for the event Rheumatoid arthritis. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Event seriousness assessed as per medical judgement.