Arthus reaction; arm hot to touch; swelling is 3cm around the injection site and it's more painful; Area of injection red; swelling is 3cm around the injection site and it's more painful/Arm felt sore; Inflammation; Allergic Rash; This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of TYPE III IMMUNE COMPLEX MEDIATED REACTION (Arthus reaction) in a 53-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 011J20A and 030L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Blood pressure high, Hyperlipidemia, Allergy (skin allergy) and Nasal allergy (nasal allergies). Concomitant products included CETIRIZINE HYDROCHLORIDE (ZYRTEC ALLERGY) for Allergy, CANDESARTAN for Blood pressure high, SIMVASTATIN for Hyperlipidemia, GLUCOSAMINE, CALCIUM and VITAMIN C [ASCORBIC ACID] for an unknown indication.   On 30-Dec-2020 at 2:00 PM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 28-Jan-2021 at 2:00 PM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 07-Jan-2021, the patient experienced INJECTION SITE INFLAMMATION (Inflammation), DERMATITIS ALLERGIC (Allergic Rash), VACCINATION SITE ERYTHEMA (Area of injection red) and VACCINATION SITE PAIN (swelling is 3cm around the injection site and it's more painful/Arm felt sore). On 07-Jan-2021 at 10:00 AM, the patient experienced VACCINATION SITE WARMTH (arm hot to touch) and VACCINATION SITE SWELLING (swelling is 3cm around the injection site and it's more painful). On an unknown date, the patient experienced TYPE III IMMUNE COMPLEX MEDIATED REACTION (Arthus reaction) (seriousness criterion medically significant). The patient was treated with PARACETAMOL (TYLENOL) at a dose of 1 dosage form and HYDROCORTISONE at a dose of 1 dosage form. On 10-Jan-2021, VACCINATION SITE WARMTH (arm hot to touch), VACCINATION SITE ERYTHEMA (Area of injection red) and VACCINATION SITE SWELLING (swelling is 3cm around the injection site and it's more painful) had resolved. At the time of the report, TYPE III IMMUNE COMPLEX MEDIATED REACTION (Arthus reaction), INJECTION SITE INFLAMMATION (Inflammation), DERMATITIS ALLERGIC (Allergic Rash) and VACCINATION SITE PAIN (swelling is 3cm around the injection site and it's more painful/Arm felt sore) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Skin test negative: negative (Negative) Doctor said might have been Arthus reaction..         On January 7 2021 (8 days after the first vaccine),the patient developed a red welt  hot to the touch and swollen and painful.  The reporter stated they applied ice and hydrocortisone cream with the welt lasted for three to fours days showing signs of improvement each day. The patient went to the immunologist for patch testing to ensure they were not allergic to an ingredient of the vaccines in order to schedule the second dose.  Patch testing came negative and physician concluded it could have been an Arhus reaction. The reporter stated they did not have a similar reaction with the second shot.  The patient did feel tired, had a headache and was febrile but symptoms disappeared in 24 hrs. (on 23-Jun-2021 per Source Document) Patient applied Ice to treat the described red welt and hot feeling. Patients doctor states the events Area of injection red, swollen and hot to the touch  can be due to Arthus reaction confirming by Negative patch test. Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.   This case was linked to MOD-2021-233221 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 23-Jun-2021: Significant Follow-up contains updated patient demographic details, Medical history, Lab data, Vaccine and facility information, Concomitant medication, Treatment medication, New events and Updated event outcome: Outcome of Area of injection red, swollen and hot to touch updated to recovered/resolved from Unknown. As per MA data corrections Arm felt sore event was removed.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.