Cellulitis of my right arm; He gave me the injection subcutaneously, in the back of my arm; low grade fever; chills; This spontaneous case was reported by a nurse and describes the occurrence of CELLULITIS (Cellulitis of my right arm) in a 60-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 045J21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included MS.    On 02-Dec-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Subcutaneous) 1 dosage form. On 02-Dec-2021, the patient experienced INCORRECT ROUTE OF PRODUCT ADMINISTRATION (He gave me the injection subcutaneously, in the back of my arm), PYREXIA (low grade fever) and CHILLS (chills). On 04-Dec-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced CELLULITIS (Cellulitis of my right arm) (seriousness criterion medically significant). The patient was treated with DOXYCYCLINE for Cellulitis, at a dose of 100 mg twice a day. On 02-Dec-2021, INCORRECT ROUTE OF PRODUCT ADMINISTRATION (He gave me the injection subcutaneously, in the back of my arm) had resolved. At the time of the report, CELLULITIS (Cellulitis of my right arm), PYREXIA (low grade fever) and CHILLS (chills) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Subcutaneous), the reporter did not provide any causality assessments.   No Concomitant medications were reported.  Patient went off her immunosuppressant medication when Covid-19 1st hit.  It was reported that patient was injured by the person administering the vaccine. On 04-Dec-2021, patient went to the urgent care center. They diagnosed her with Cellulitis of right arm.  Patient was concerned when she saw the pharmacist gave her daughter the injection, because it looked like he gave it real low in her deltoid. Patient notified him that she was a nurse and told him that it goes 2 finger widths below acromion process. The Pharmacist said 'we don't give injections there. It can cause nerve damage. Patient received the injection subcutaneously, in the back of her arm.  Patient called her Dr office and told them what happened. He said in couple of months, maybe she can get another half dose.  Company comment: This is a spontaneous case concerning a 60-year-old, female patient with no relevant medical history, who experienced the unexpected serious event of cellulitis and non serious listed events of pyrexia (low grade fever) and chills. Allegedly the patient received third dose of mRNA-1273 vaccine through subcutaneous route of administration the same day the patient developed chills and low grade fever then after 2 days the patient was diagnosed with cellulitis, right arm and was prescribed with Doxycycline 100 mg twice daily for 10 days. The outcome of the events were unknown. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2021-408554 (Patient Link).; Sender's Comments: This is a spontaneous case concerning a 60-year-old, female patient with no relevant medical history, who experienced the unexpected serious event of cellulitis and non serious listed events of pyrexia (low grade fever) and chills. Allegedly the patient received third dose of mRNA-1273 vaccine through subcutaneous route of administration the same day the patient developed chills and low grade fever then after 2 days the patient was diagnosed with cellulitis, right arm and was prescribed with Doxycycline 100 mg twice daily for 10 days. The outcome of the events were unknown. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.