she noticed that there was a quarter size welt on her arm at the injection site; This spontaneous case was reported by a patient and describes the occurrence of URTICARIA (she noticed that there was a quarter size welt on her arm at the injection site) in a 38-year-old female patient who received mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (batch no. AS7644C) for COVID-19 prophylaxis.     The patient's past medical history included Sinus infection (very bad sinus infection which had never experienced before.) in November 2019, Exposure to COVID-19 (proximity to a person who had return from covid effect region.) in November 2019 and Unwell (Not well) in November 2019. Previously administered products included for Product used for unknown indication: johnson & johnson vaccine (1 st dose) on 02-Apr-2021, Pifizer (2nd dose) on 07-Jan-2022, Flu shot (3 years ago and got a 3 inch oval shaped welt and it extended from fingertips to shoulders). Past adverse reactions to the above products included Hives with Flu shot; and No adverse event with Pifizer and johnson & johnson vaccine. Concurrent medical conditions included Hereditary alpha tryptasemia (Has a genetic predisposition to allergic reactions), Fruit allergy (jalapeno and cucumber) and Food allergy (chocolate).    On 24-Aug-2023, the patient received third dose of mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (unknown route) 1 dosage form. On 24-Aug-2023,  after starting mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)), the patient experienced URTICARIA (she noticed that there was a quarter size welt on her arm at the injection site). The patient was treated with DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]) at an unspecified dose and frequency. At the time of the report, URTICARIA (she noticed that there was a quarter size welt on her arm at the injection site) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In June 2022, SARS-CoV-2 test: Positive.     For mRNA-1273 BIVALENT .222 (MODERNA COVID-19 VACCINE, BIVALENT (ORIGINAL AND OMICRON BA.4/BA.5)) (Unknown), the reporter did not provide any causality assessments.   Concomitant product use was not provided by the reporter. On the night of 24-AUG-2023, patient started experiencing itching around the injection area. On 25-Aug-2023 morning patient noticed that patient had a quarter size welt on arm at the injection site. Patient felt there was heat that had started to radiate around that welt and was itching as well. On 25-Aug-2023 by 10:40 am the welt size had increased to 2 inches. Patient still had heat radiating from welt and it was itching. Patient arm was swollen and was itchy from elbow to shoulder.  By midday Saturday, 26-AUG-2023, the welt size was around 3.5 inches. Patient arm had been struck by a baseball and patient was angry, because of itchiness in welt. It had been reported that the area of the welt was 8 degrees warmer as compared to the rest of body.  Patient spoke with the pharmacist who gave the injection, and it had been informed to patient that itchiness was only a localized, normal reaction. Patient also experienced little red dots that were started to show up on upper right arm.  Patient reported that overall reaction was improved after treatment medication. However, patient had soreness in arm and patient still had itching. Additionally, patient had huge mark on arm. Patient did not have any difficulty in breathing.   Most recent FOLLOW-UP information incorporated above includes: On 28-Aug-2023: Live follow up has been appended.