Rheumatoid arthritis progression and symptoms came back; Lack of effect; Nodule on foot; Increased stiffness in morning; Headache; Felt very tired; Soreness on the arm; This spontaneous case was reported by a physician (subsequently medically confirmed) and describes the occurrence of RHEUMATOID ARTHRITIS (Rheumatoid arthritis progression and symptoms came back), PAIN IN EXTREMITY (Soreness on the arm), NODULE (Nodule on foot), MUSCULOSKELETAL STIFFNESS (Increased stiffness in morning) and DRUG INEFFECTIVE (Lack of effect) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 011L20A and 012M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Nodule on extremity in January 2019, Non-smoker, Abstains from alcohol and Rheumatoid arthritis. Concurrent medical conditions included Sulfonamide allergy (Manifested by rash), Peanut allergy (Manifested by rash) and Drug allergy (ACE inhibitors manifested by rash). Concomitant products included DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]) for Allergy, ADALIMUMAB (HUMIRA) for Rheumatoid arthritis, HYDROXYCHLOROQUINE SULFATE (PLAQUENIL [HYDROXYCHLOROQUINE SULFATE]) for Stiffness and Rheumatoid arthritis.   On 02-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 30-Jan-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 03-Jan-2021, the patient experienced PAIN IN EXTREMITY (Soreness on the arm). On 30-Jan-2021, the patient experienced HEADACHE (Headache) and FATIGUE (Felt very tired). In February 2021, the patient experienced NODULE (Nodule on foot) and MUSCULOSKELETAL STIFFNESS (Increased stiffness in morning). On an unknown date, the patient experienced RHEUMATOID ARTHRITIS (Rheumatoid arthritis progression and symptoms came back) and DRUG INEFFECTIVE (Lack of effect). On 05-Jan-2021, PAIN IN EXTREMITY (Soreness on the arm) had resolved. On 30-Jan-2021, HEADACHE (Headache) had resolved. On 01-Feb-2021, FATIGUE (Felt very tired) had resolved. At the time of the report, RHEUMATOID ARTHRITIS (Rheumatoid arthritis progression and symptoms came back) outcome was unknown, NODULE (Nodule on foot) and MUSCULOSKELETAL STIFFNESS (Increased stiffness in morning) had not resolved and DRUG INEFFECTIVE (Lack of effect) had resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered PAIN IN EXTREMITY (Soreness on the arm), HEADACHE (Headache) and FATIGUE (Felt very tired) to be probably related and NODULE (Nodule on foot) and MUSCULOSKELETAL STIFFNESS (Increased stiffness in morning) to be unlikely related. No further causality assessments were provided for RHEUMATOID ARTHRITIS (Rheumatoid arthritis progression and symptoms came back) and DRUG INEFFECTIVE (Lack of effect).    Treatment for event included prednisone and paracetamol.  Based on current available information and the temporal association between product use and the start date of the events a causal relationship cannot be excluded except for the events of Nodule and Musculoskeletal stiffness which the HCP reporter states are unlikely related.   This case was linked to MOD-2021-096076 (Patient Link).; Sender's Comments: Based on current available information and the temporal association between product use and the start date of the events a causal relationship cannot be excluded except for the events of Nodule and Musculoskeletal stiffness which the HCP reporter states are unlikely related.