Coughing; Flu-like symptoms; Lost weight; Pain in arm/Sore arm; Rheumatoid arthritis flare up/Rheumatoid arthritis flare; This spontaneous case was reported by a patient and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up/Rheumatoid arthritis flare) in a 54-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 products included non-company products ADALIMUMAB (HUMIRA) for Rheumatoid arthritis and TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 vaccination.    Concurrent medical conditions included Rheumatoid arthritis (Moderate to severe rheumatoid arthritis).   In 2021, the patient received first dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) 1 dosage form. In 2021, received second dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) dosage was changed to 1 dosage form. On 22-Apr-2022, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) at an unspecified dose. On 23-Apr-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up/Rheumatoid arthritis flare) (seriousness criterion medically significant). On an unknown date, the patient experienced COUGH (Coughing), INFLUENZA LIKE ILLNESS (Flu-like symptoms), WEIGHT DECREASED (Lost weight) and PAIN IN EXTREMITY (Pain in arm/Sore arm). At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis flare up/Rheumatoid arthritis flare), COUGH (Coughing), INFLUENZA LIKE ILLNESS (Flu-like symptoms), WEIGHT DECREASED (Lost weight) and PAIN IN EXTREMITY (Pain in arm/Sore arm) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Weight: decreased.         No concomitant medications were reported.  No treatment medications were reported.  For Pfizer BioNtech COVID-19 Vaccine (Tozinameran), causality as per reporter for the events of coughing, rheumatoid arthritis flareup, pain in arm, flu-like symptoms, lost weight was reported as possible.  For Humira(Adalimumab), reporter's causality for the events of coughing and lost weight was no reasonable possibility, for rheumatoid arthritis flare up was a reasonable possibility, for sore arm and flu-like symptoms was not provided.  It was unknown if patient was enrolled in a COVID-19 vaccine trial.  Company Comment: This is a spontaneous case, concerning a 54-year-old, female patient with concurrent condition of Rheumatoid arthritis, who experienced the serious, medically significant, unexpected AESI of Rheumatoid arthritis (Reported as Rheumatoid arthritis flare up), the next day after the administration of the 3rd dose of mRNA-1273 vaccine (Booster dose). Patient had previously received a Pfizer COVID-19 vaccine (interchange of vaccine products was noted). Very limited information is available regarding diagnostic work-up to support the current diagnosis and treatment received. The outcome at the time of the report was Unknown. The concurrent condition remains as a contributor for the event; due to the clinical course of Rheumatoid arthritis, may presents flare up of the disease. Pfizer vaccine could be a confounder for the event, also due to interchange of vaccine product. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case, concerning a 54-year-old, female patient with concurrent condition of Rheumatoid arthritis, who experienced the serious, medically significant, unexpected AESI of Rheumatoid arthritis (Reported as Rheumatoid arthritis flare up), the next day after the administration of the 3rd dose of mRNA-1273 vaccine (Booster dose). Patient had previously received a Pfizer COVID-19 vaccine (interchange of vaccine products was noted). Very limited information is available regarding diagnostic work-up to support the current diagnosis and treatment received. The outcome at the time of the report was Unknown. The concurrent condition remains as a contributor for the event; due to the clinical course of Rheumatoid arthritis, may presents flare up of the disease. Pfizer vaccine could be a confounder for the event, also due to interchange of vaccine product. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.