Rheumatoid arthritis; This is a literature report for the following literature source(s): Private.   A 72-year-old female patient received BNT162b2 (BNT162B2), as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "type I diabetes mellitus" (unspecified if ongoing). The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (DOSE 1, SINGLE), for Covid-19 immunization. The following information was reported: RHEUMATOID ARTHRITIS (medically significant), 1 day after the suspect product(s) administration, outcome "recovering". The patient underwent the following laboratory tests and procedures: Antibody test: greater than 250; Antinuclear antibody: negative; Hepatitis B virus test: negative; Hepatitis C virus test: negative; HIV test: negative; classification criteria for rheumatoid arthritis: 2010 ACR classification criteria; for synovitis at the, notes: bilateral second to fourth MCP joints, second to fourth PIP joints, and first to fifth MTP joints; Rheumatoid factor: greater than 130, notes: elevated; SARS-CoV-2 test: negative; X-ray limb: negative; negative. Therapeutic measures were taken as a result of rheumatoid arthritis.  Clinical course: The patient was initially seen in primary care and then referred to rheumatology for further evaluation and management. Clinical data were obtained through review of the electronic medical record, and each patient is being followed up in the rheumatology clinic. The 72-year-old woman presented to clinic rheumatology with 2 months of symmetric polyarthritis involving the MCP (metacarpophalangeal) joints, PIP (proximal interphalangeal) joints, and metatarsophalangeal (MTP) joints with prolonged morning stiffness. Symptom onset occurred 1 day after completing the Pfizer-BioNTech vaccination series. The patient had a history of type I diabetes mellitus, no history COVID infection, and no family history of autoimmune disease. The patient never received immunosuppression in the past, and no medication changes were made at the time of vaccination. Examination was remarkable for synovitis at the bilateral second to fourth MCP joints, second to fourth PIP joints, and first to fifth MTP joints. Laboratory evaluation FANA test was negative, Normal ESR and CRP. Hand and foot radiographs demonstrated no erosive changes. The patient met the 2010 ACR (Urine albumin to creatinine ratio) classification criteria for rheumatoid arthritis. She was initially treated with prednisone and achieved clinical remission with leflunomide and golimumab.  Conclusion: The author cannot determine if these rheumatic diseases were clearly caused by or correlated with Pfizer-BioNTech vaccinations but feel that the temporal association was compelling and reportable. At this point in the pandemic, new-onset autoimmune disease following COVID-19 vaccination has become a well-described phenomenon. Although the pathogenesis was incompletely understood, molecular mimicry was among the proposed mechanisms leading to the development of autoimmune disease and provided a relevant basis for our discussion of possible adverse events related to vaccination. Each of the patient reported involved the development of new rheumatic disease that was temporally associated with mRNA vaccination against COVID-19. In each case, symptoms developed within 1 week after the second dose of vaccination, which was a reasonable interval for antibody formation and autoimmune-mediated damage to occur. Of the possible autoimmune mechanisms, molecular mimicry seems plausible based on the significant sequence homology between the COVID spike protein and human proteins. Whether there exists a causal or contributory relationship between COVID-19 mRNA vaccination and the development of autoimmune rheumatic disease remains to be determined. Although the absolute risk for development of autoimmune disease following mRNA vaccination against COVID-19 seems to be low, further research was warranted to delineate if there was a true causal relationship. Ultimately, further research is needed to establish if there is a true connection between the two. Sender's Comments: Based on known drug safety profile, there is reasonable possibility of causal association between the event RHEUMATOID ARTHRITIS and BNT162B2.      The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.