He is sure he has arthritis; Swollen ankles/Swollen knees; discomfort in all his joints like he had never had; his shoulder were tender and stiff; he has some aches and pains here and there, but this was enough pain to wake him up; knees, ankles, small joint of his hands were tender and stiff; pain in all his joints like he had never had/his shoulders, knees, ankles, small joint of his hands were tender; This spontaneous case was reported by a physician and describes the occurrence of ARTHRITIS (He is sure he has arthritis), JOINT SWELLING (Swollen ankles/Swollen knees), MUSCULOSKELETAL DISCOMFORT (discomfort in all his joints like he had never had), MUSCULOSKELETAL STIFFNESS (his shoulder were tender and stiff) and PAIN (he has some aches and pains here and there, but this was enough pain to wake him up) in a male patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   In February 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In March 2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In October 2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced ARTHRITIS (He is sure he has arthritis), JOINT SWELLING (Swollen ankles/Swollen knees), MUSCULOSKELETAL DISCOMFORT (discomfort in all his joints like he had never had), MUSCULOSKELETAL STIFFNESS (his shoulder were tender and stiff), PAIN (he has some aches and pains here and there, but this was enough pain to wake him up), JOINT STIFFNESS (knees, ankles, small joint of his hands were tender and stiff) and ARTHRALGIA (pain in all his joints like he had never had/his shoulders, knees, ankles, small joint of his hands were tender). At the time of the report, ARTHRITIS (He is sure he has arthritis), JOINT SWELLING (Swollen ankles/Swollen knees), MUSCULOSKELETAL DISCOMFORT (discomfort in all his joints like he had never had), MUSCULOSKELETAL STIFFNESS (his shoulder were tender and stiff), PAIN (he has some aches and pains here and there, but this was enough pain to wake him up), JOINT STIFFNESS (knees, ankles, small joint of his hands were tender and stiff) and ARTHRALGIA (pain in all his joints like he had never had/his shoulders, knees, ankles, small joint of his hands were tender) was resolving.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   No concomitant medications were reported. The rheumatologist injected steroid into patient's knees and ankles. Patient stated that he believes the symptoms were somewhat better, but they were still there, he has suffered it ever since he was awakened with the symptoms. Patient also reported no side effects were experienced by Primary doses.  Company comment: This spontaneous case concerns a  male patient of an unknown age, with no reported medical history, who experienced the non-serious, unexpected AESI of arthritis. Patient received first 2 doses of mRNA 1273 COVID-19 vaccine without any adverse event, and then received the third dose 7 months after. On unknown date after the third dose of mRNA 1273 vaccine, patient was awakened due to joint pain, discomfort and stiffness in his shoulders, knees, ankles, and small joints of his hands. Patient, who is a doctor, believed he had arthritis. He consulted a rheumatologist after 2 days due to joint swelling, and got his knees and ankles injected with steroids. At the time of report, events were resolving. The benefit-risk relationship of mRNA 1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a  male patient of an unknown age, with no reported medical history, who experienced the non-serious, unexpected AESI of arthritis. Patient received first 2 doses of mRNA 1273 COVID-19 vaccine without any adverse event, and then received the third dose 7 months after. On unknown date after the third dose of mRNA 1273 vaccine, patient was awakened due to joint pain, discomfort and stiffness in his shoulders, knees, ankles, and small joints of his hands. Patient, who is a doctor, believed he had arthritis. He consulted a rheumatologist after 2 days due to joint swelling, and got his knees and ankles injected with steroids. At the time of report, events were resolving. The benefit-risk relationship of mRNA 1273 vaccine is not affected by this report.