Swelling of L knee; Arm hurt at booster COVID-19 injection site; This spontaneous case was reported by a consumer and describes the occurrence of JOINT SWELLING (Swelling of L knee) in a 62-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 product included non-company product ADALIMUMAB (HUMIRA) solution for injection for Rheumatoid arthritis.    The patient's past medical history included Knee total replacement in October 2021. Concurrent medical conditions included Rheumatoid arthritis.   On 04-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 01-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In 2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) CF. In 2021, the patient experienced VACCINATION SITE PAIN (Arm hurt at booster COVID-19 injection site). In December 2021, the patient experienced JOINT SWELLING (Swelling of L knee) (seriousness criterion medically significant). At the time of the report, JOINT SWELLING (Swelling of L knee) and VACCINATION SITE PAIN (Arm hurt at booster COVID-19 injection site) outcome was unknown.            This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in   In Oct 2021, the patient had total left knee replacement. She was off Humira, about three weeks out, and felt like someone tapping on her hands, then her wrists were hurting. In Dec 2021, she had swelling in left knee. She had side effects from Covid-19 booster. Underneath her arm hurt, at booster Covid-19 injection site. It was unknown if patient was enrolled in a COVID-19 Vaccine Trial. On 04 Mar 2021, she received 1st dose COVID-19 Vaccine manufactured by Moderna. On 01 Apr 2021, she received 2nd dose COVID-19 Vaccine manufactured by Moderna. In 2021, she received booster dose COVID-19 Vaccine manufactured by Moderna. Adverse event information provided by her was not related to Covid vaccine.  the reporter's causality for the event(s) of total left knee replacement, underneath arm hurt at booster covid-19 injection site, swelling in left knee, felt like someone tapping on hands and wrists were hurting/pain was not provided.  No concomitant medication was provided by reporter. No treatment medication was provided by reporter.  CC: This spontaneous case concerns a 62-year-old, female patient with a concurrent condition of rheumatoid arthritis treated with adalimumab, who experienced an unexpected, medically significant event of Joint swelling, left knee in association with a 3rd dose of mRNA-1273 vaccine. Exact onset latency of said event relative to vaccination cannot be determined with unspecified event's onset date and vaccination date. Reportedly, the patient underwent total left knee replacement approximately 2 months before the event's onset. Patient was also off Humira for about 3 weeks. Further details on the clinical course, diagnostics, and treatments were not reported. Vaccination history included a 2-dose primary series and a 3rd dose of mRNA-1273 vaccine. Patient's underlying rheumatoid arthri; Sender's Comments: This spontaneous case concerns a 62-year-old, female patient with a concurrent condition of rheumatoid arthritis treated with adalimumab, who experienced an unexpected, medically significant event of Joint swelling, left knee in association with a 3rd dose of mRNA-1273 vaccine. Exact onset latency of said event relative to vaccination cannot be determined with unspecified event's onset date and vaccination date. Reportedly, the patient underwent total left knee replacement approximately 2 months before the event's onset. Patient was also off Humira for about 3 weeks. Further details on the clinical course, diagnostics, and treatments were not reported. Vaccination history included a 2-dose primary series and a 3rd dose of mRNA-1273 vaccine. Patient's underlying rheumatoid arthritis, temporary cessation of Humira therapy, and history of recent left knee surgery remain as confounders in this case. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.