very weak; Polymyalgia Rheumatica; Giant Cell Arteritis; This spontaneous case was reported by a consumer and describes the occurrence of POLYMYALGIA RHEUMATICA (Polymyalgia Rheumatica) and GIANT CELL ARTERITIS (Giant Cell Arteritis) in an 85-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 047C21A, 046B21A and 007A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Arthritis (diagnosed 30 years ago), Seafood allergy and Shellfish allergy. Concomitant products included OMEPRAZOLE, GABAPENTIN, PARACETAMOL (TYLENOL [PARACETAMOL]), AMITRIPTYLINE, ATORVASTATIN and CALCIUM for an unknown indication.   On 20-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 01-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In November 2021, the patient experienced POLYMYALGIA RHEUMATICA (Polymyalgia Rheumatica) (seriousness criterion medically significant) and GIANT CELL ARTERITIS (Giant Cell Arteritis) (seriousness criterion medically significant). On an unknown date, the patient experienced ASTHENIA (very weak). The patient was treated with PREDNISONE ongoing since an unknown date for Giant cell arteritis and Polymyalgia rheumatica, at a dose of 40 milligram once a day. At the time of the report, POLYMYALGIA RHEUMATICA (Polymyalgia Rheumatica), GIANT CELL ARTERITIS (Giant Cell Arteritis) and ASTHENIA (very weak) outcome was unknown.            Additional concomitant medication included multivitamin.  Patient was diagnosed with Giant Cell Arteritis and Polymyalgia Rheumatica either on 03-Nov-2021 or 05-Nov-2021.  Company comment: This spontaneous case concerns a 85-year-old female patient with a relevant medical history of Arthritis, who experienced the unexpected serious (medically significant) events of Polymyalgia rheumatica and Giant cell arteritis after mRNA- 1273 vaccine. The events occurred approximately 2 to 5 days after the booster dose of mRNA- 1273 vaccine. Very limited information is available regarding clinical manifestations and diagnostic work-up. Treatment with prednisone 40mg once a day was prescribed.  Previous history of arthritis might be a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 85-year-old female patient with a relevant medical history of Arthritis, who experienced the unexpected serious (medically significant) events of Polymyalgia rheumatica and Giant cell arteritis after mRNA- 1273 vaccine. The events occurred approximately 2 to 5 days after the booster dose of mRNA- 1273 vaccine. Very limited information is available regarding clinical manifestations and diagnostic work-up. Treatment with prednisone 40mg once a day was prescribed.  Previous history of arthritis might be a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.