Cellulitis; swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside; That area was hot; swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside; That area was itchy; This spontaneous case was reported by a consumer and describes the occurrence of CELLULITIS (Cellulitis) in a 71-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 939909, 041821A and 044821A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Pacemaker insertion (cardiac). Concurrent medical conditions included Rheumatoid arthritis, Clotting disorder and Haemophilia.   On 19-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 16-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 21-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 22-Nov-2021, the patient experienced VACCINATION SITE MASS (swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside), VACCINATION SITE WARMTH (That area was hot ), VACCINATION SITE ERYTHEMA (swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside) and VACCINATION SITE PRURITUS (That area was itchy). On 30-Nov-2021, the patient experienced CELLULITIS (Cellulitis) (seriousness criterion medically significant). The patient was treated with CLINDAMYCIN for Cellulitis, at a dose of UNK dosage form. At the time of the report, CELLULITIS (Cellulitis) outcome was unknown and VACCINATION SITE MASS (swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside), VACCINATION SITE WARMTH (That area was hot ), VACCINATION SITE ERYTHEMA (swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside) and VACCINATION SITE PRURITUS (That area was itchy) had not resolved.            Concomitant medication information was not provided by the reporter.  Following the 3rd dose of the vaccine, the next morning she noticed a swath of red across her arm with knots about 8 inches wide going from the outside of her arm to the inside. That area was hot and itchy and was still present. She saw her primary care doctor on 30Nov2021 where she was prescribed clindamycin for cellulitis. She then started taking the clindamycin yesterday, 2Dec2021. Her symptoms from the cellulitis have continued until today. She also states she "did have some of the other side effects." Company Comment This case concerns a 71-year-old, female patient with previous relevant medical history of pacemaker insertion (cardiac), rheumatoid arthritis, clotting disorder and Haemophilia, who experienced the unexpected events of cellulitis. The events occurred 1 day after the third dose of mRNA-1273. The rechallenge was not applicable since the events happened after the third dose. The medical history of clotting disorder and Haemophilia remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report.   This case was linked to MOD-2021-404671 (Patient Link).; Sender's Comments: This case concerns a 71-year-old, female patient with previous relevant medical history of pacemaker insertion (cardiac), rheumatoid arthritis, clotting disorder and Haemophilia, who experienced the unexpected events of cellulitis. The events occurred 1 day after the third dose of mRNA-1273. The rechallenge was not applicable since the events happened after the third dose. The medical history of clotting disorder and Haemophilia remains a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report.