Injection site feels hot to the touch; Excruciating body aches all over; Fibromyalgia and RA have completely flared up; Fibromyalgia and RA have completely flared up; Missed 2 days of work; Welt is itchy; Big welt at the injection site; Big red circle around the injection site; This spontaneous case was reported by a consumer and describes the occurrence of RHEUMATOID ARTHRITIS (Fibromyalgia and RA have completely flared up) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 032C21A and 032C21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Fibromyalgia since an unknown date and Rheumatoid arthritis since an unknown date. Concomitant products included HYDROXYCHLOROQUINE SULFATE (PLAQUENIL [HYDROXYCHLOROQUINE SULFATE]), GABAPENTIN, CURCUMA LONGA (TURMERIC [CURCUMA LONGA]), DULOXETINE and ETANERCEPT (ENBREL) for an unknown indication.   On 10-Nov-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 08-Dec-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 08-Dec-2021, the patient experienced PAIN (Excruciating body aches all over). In December 2021, the patient experienced RHEUMATOID ARTHRITIS (Fibromyalgia and RA have completely flared up) (seriousness criterion medically significant), FIBROMYALGIA (Fibromyalgia and RA have completely flared up), IMPAIRED WORK ABILITY (Missed 2 days of work), VACCINATION SITE PRURITUS (Welt is itchy), VACCINATION SITE URTICARIA (Big welt at the injection site) and VACCINATION SITE ERYTHEMA (Big red circle around the injection site). On an unknown date, the patient experienced VACCINATION SITE WARMTH (Injection site feels hot to the touch). The patient was treated with PARACETAMOL (TYLENOL [PARACETAMOL]) for Adverse event, at an unspecified dose and frequency. At the time of the report, RHEUMATOID ARTHRITIS (Fibromyalgia and RA have completely flared up), FIBROMYALGIA (Fibromyalgia and RA have completely flared up), IMPAIRED WORK ABILITY (Missed 2 days of work) and PAIN (Excruciating body aches all over) had not resolved and VACCINATION SITE WARMTH (Injection site feels hot to the touch), VACCINATION SITE PRURITUS (Welt is itchy), VACCINATION SITE URTICARIA (Big welt at the injection site) and VACCINATION SITE ERYTHEMA (Big red circle around the injection site) outcome was unknown.            Patient received second dose about 11 am-12 pm that day and about 10-11 pm that evening she developed excruciating body aches all over and then overnight it got out of control. She has a history of fibromyalgia and RA in which she took Enbrel, Plaquenil, gabapentin, duloxetine, and turmeric. Her fibromyalgia and RA have completely flared up, she has joint pain and she missed 2 days of work. Her doctor advised her to take her Enbrel one day early and she did on 09-dec-2021. He also told her to take Tylenol, hydrate and rest. This was not helping. She also stated she had a big welt at the injection site, the welt was itchy, has a big red circle around the injection site, the area around the injection site feels hot to the touch. Treatment of rest and hydration provided. Company comment: This case concerns a female patient of unknown age with medical history of fibromyalgia and rheumatoid arthritis, who experienced the unexpected serious event of rheumatoid arthritis along with other non serious events. The event occurred in the same month after the second dose of mRNA-1273. As reported, on the same day after vaccination the patient developed excruciating body aches all over and then overnight it got out of control. Her fibromyalgia and RA had completely flared up, she had joint pain and she missed 2 days of work. The rechallenge was not applicable as events occurred after second dose and no further dosing was reported or planned, based on information provided. The patient's above mentioned medical history remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This case concerns a female patient of unknown age with medical history of fibromyalgia and rheumatoid arthritis, who experienced the unexpected serious event of rheumatoid arthritis along with other non serious events. The event occurred in the same month after the second dose of mRNA-1273. As reported, on the same day after vaccination the patient developed excruciating body aches all over and then overnight it got out of control. Her fibromyalgia and RA had completely flared up, she had joint pain and she missed 2 days of work. The rechallenge was not applicable as events occurred after second dose and no further dosing was reported or planned, based on information provided. The patient's above mentioned medical history remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report.