received the one dose Johnson and Johnson and then first moderna booster as 0.5 mL; starts of as a burning type of itch,very intense in nature; skin welts / hives , then it turns into welts and hives , primarily in legs, arms, hands, and back; This spontaneous case was reported by a patient and describes the occurrence of PRURITUS (starts of as a burning type of itch,very intense in nature), URTICARIA (skin welts / hives , then it turns into welts and hives , primarily in legs, arms, hands, and back) and ACCIDENTAL OVERDOSE (received the one dose Johnson and Johnson and then first moderna booster as 0.5 mL) in a 61-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The patient's past medical history included Blood pressure abnormal. Previously administered products included for Product used for unknown indication: Janssen COVID-19 vaccine (Dose 1) on 03-Apr-2021. Past adverse reactions to the above products included No adverse event with Janssen COVID-19 vaccine. Concurrent medical conditions included Polycythemia (phlebotomies treatment every 10 weeks. It has gotten better, gets treatment every 16 weeks now) and Erythrocytosis (phlebotomies treatment every 10 weeks. It has gotten better, gets treatment every 16 weeks now). Concomitant products included PRAVASTATIN, FISH OIL and ACETYLSALICYLIC ACID (BABY ASPIRIN) for an unknown indication. On 08-Nov-2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) .5 milliliter. On 24-May-2022, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to .25 milliliter. In February 2022, the patient experienced PRURITUS (starts of as a burning type of itch,very intense in nature) and URTICARIA (skin welts / hives , then it turns into welts and hives , primarily in legs, arms, hands, and back). On an unknown date, the patient experienced ACCIDENTAL OVERDOSE (received the one dose Johnson and Johnson and then first moderna booster as 0.5 mL). The patient was treated with DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]) for Welts, at an unspecified dose and frequency. At the time of the report, PRURITUS (starts of as a burning type of itch,very intense in nature) and URTICARIA (skin welts / hives , then it turns into welts and hives , primarily in legs, arms, hands, and back) had not resolved and ACCIDENTAL OVERDOSE (received the one dose Johnson and Johnson and then first moderna booster as 0.5 mL) outcome was unknown.  No other vaccines given within 1 month prior to Moderna COVID-19 vaccine. Patient did not have any allergies. Patient never had COVID positive test or diagnosis. It was reported that 2.5 months after receiving the 1st dose of vaccine, he started experiencing welts and hives. This started occurring around Feb 2022. He said that it started off intense and after about 4 days with the suggestion of his wife, he started taking Benadryl for this symptom. The Benadryl seems to calm down the effect. The symptoms come and go, and patient not had to take the blood pressure medication recently as blood pressure had been in control. Most recent FOLLOW-UP information incorporated above includes: On 12-Aug-2022: Follow-up received includes patient details, concomitant medication , events, and narrative updated.