Rheumatoid arthritis flare up starting on entire left side; Site of vaccination painful/ Soreness at injection site; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up starting on entire left side) in a 76-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 Rheumatoid arthritis.   On an unknown date, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form and ADALIMUMAB (HUMIRA) (Subcutaneous) Citrate free. On 04-Dec-2021, the patient experienced VACCINATION SITE PAIN (Site of vaccination painful/ Soreness at injection site). On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up starting on entire left side) (seriousness criterion medically significant). In December 2021, VACCINATION SITE PAIN (Site of vaccination painful/ Soreness at injection site) had resolved. At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up starting on entire left side) had not resolved.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       No Concomitant medication were reported.  It was unknown if patient was enrolled in a COVID-19 Vaccine Trial. Company comment-This spontaneous case concerns a female patient aged 76 years with reported concurrent condition of rheumatoid arthritis on Humira, experienced unexpected serious (medically significant) AESI of Rheumatoid arthritis (reported as Rheumatoid arthritis flare up) on unknown dates in the context of a unspecified dose of mRNA-1273 vaccination. No further information on detailed clinical course, investigations and treatment was available in the report.  Outcome of the event was not resolved at the time of report. Relevant concurrent condition of rheumatoid arthritis remains a confounder to the event. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Event seriousness assessed as per medical judgement.  The reporter's causality for the event(s) of SORENESS AT INJECTION SITE AFTER COVID VACCINATION and RHEUMATOID ARTHRITIS FLARE UPS STARTING ON ENTIRE LEFT SIDE with HUMIRA(ADALIMUMAB) was no reasonable possibility.  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.  It was reported that Relevant Laboratory & Other Diagnostic unknown Test done on 06-Dec-2021 and stated  waiting of result.  No treatment medication were reported.   Reporter did not allow further contact; Sender's Comments: This spontaneous case concerns a female patient aged 76 years with reported concurrent condition of rheumatoid arthritis on Humira, experienced unexpected serious (medically significant) AESI of Rheumatoid arthritis (reported as Rheumatoid arthritis flare up) on unknown dates in the context of a unspecified dose of mRNA-1273 vaccination. No further information on detailed clinical course, investigations and treatment was available in the report.  Outcome of the event was not resolved at the time of report. Relevant concurrent condition of rheumatoid arthritis remains a confounder to the event. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Event seriousness assessed as per medical judgement.