these effects are driving her insane & keeping her from getting the booster; sore arm both times; back was flared at times; everywhere she had previously inflamed joints & ligaments flared up; tenderness in her arm; only pain she has had that was not previously inflamed is her right hip & that was bad enough to keep her awake at night; This spontaneous case was reported by a nurse and describes the occurrence of FEELING ABNORMAL (these effects are driving her insane & keeping her from getting the booster), PAIN IN EXTREMITY (sore arm both times), MUSCULOSKELETAL DISCOMFORT (back was flared at times), ARTHRITIS (everywhere she had previously inflamed joints & ligaments flared up) and TENDERNESS (tenderness in her arm) in a 66-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 013L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Osteopenia and Knee replacement (Left knee replacement). Concurrent medical conditions included Osteoarthritis, Raynaud's disease and Costochondritis.    On 15-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced FEELING ABNORMAL (these effects are driving her insane & keeping her from getting the booster), PAIN IN EXTREMITY (sore arm both times), MUSCULOSKELETAL DISCOMFORT (back was flared at times), ARTHRITIS (everywhere she had previously inflamed joints & ligaments flared up), TENDERNESS (tenderness in her arm) and ARTHRALGIA (only pain she has had that was not previously inflamed is her right hip & that was bad enough to keep her awake at night). The patient was treated with FLUVOXAMINE MALEATE (LUVOX [FLUVOXAMINE MALEATE]) for Adverse event, at an unspecified dose and frequency and ASPIRIN [ACETYLSALICYLIC ACID] for Adverse event, at a dose of 1 dosage form once a day. At the time of the report, FEELING ABNORMAL (these effects are driving her insane & keeping her from getting the booster), PAIN IN EXTREMITY (sore arm both times), MUSCULOSKELETAL DISCOMFORT (back was flared at times), ARTHRITIS (everywhere she had previously inflamed joints & ligaments flared up) and ARTHRALGIA (only pain she has had that was not previously inflamed is her right hip & that was bad enough to keep her awake at night) outcome was unknown and TENDERNESS (tenderness in her arm) had resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) dosing remained unchanged.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant medications not reported by the reporter. Treatment also included steroid dosepack for adverse events. This is a spontaneous case concerning a 66-year-old female patient with relevant medical history of Osteoarthritis, who experienced non serious, AESI, unexpected event of arthritis. The event occurred on an unknown date after the first dose of mRNA-1273 vaccine. Rechallenge is not applicable since outcome of the event is unknown. Medical history of Osteoarthritis remains a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2021-387028 (Patient Link).; Sender's Comments: This is a spontaneous case concerning a 66-year-old female patient with relevant medical history of Osteoarthritis, who experienced non serious, AESI, unexpected event of arthritis. The event occurred on an unknown date after the first dose of mRNA-1273 vaccine. Rechallenge is not applicable since outcome of the event is unknown. Medical history of Osteoarthritis remains a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.