This spontaneous case was reported by a consumer and describes the occurrence of URTICARIA (He has hives all over his body), PRURITUS (All over body was itching), OXYGEN SATURATION DECREASED (Oxygen saturation decreased), TACHYCARDIA (Heartbeat was very fast) and RASH (His whole body had a rash) in a 65-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below. Co-suspect product included non-company product INFLUENZA VACCINE for Influenza. No Medical History information was reported. On 19-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 17-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 17-Nov-2021, the patient received dose of INFLUENZA VACCINE (unknown route) 1 dosage form. On 17-Nov-2021, the patient experienced CHILLS (First and second night after booster he had chills). On 22-Nov-2021, the patient experienced URTICARIA (He has hives all over his body), PRURITUS (All over body was itching), OXYGEN SATURATION DECREASED (Oxygen saturation decreased), TACHYCARDIA (Heartbeat was very fast) and RASH (His whole body had a rash). The patient was treated with FAMOTIDINE (PEPCID [FAMOTIDINE]) (intravenous) for Adverse event, at a dose of 20 mg; HYDROXYZINE (ATARAX [HYDROXYZINE]) for Adverse event, at an unspecified dose and frequency; PREDNISONE for Adverse event, at an unspecified dose and frequency and TRIAMCINOLONE ACETONIDE for Rash, at an unspecified dose and frequency. At the time of the report, URTICARIA (He has hives all over his body), PRURITUS (All over body was itching), OXYGEN SATURATION DECREASED (Oxygen saturation decreased), TACHYCARDIA (Heartbeat was very fast), RASH (His whole body had a rash) and CHILLS (First and second night after booster he had chills) outcome was unknown. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 22-Nov-2021, Heart rate: high (High) High, heartbeat is very fast. On 22-Nov-2021, Oxygen saturation: low (Low) Low. Concomitant product use was not provided by the reporter. Patient got his booster shot on 17-Nov-2021 and flu shot on the same day as well. First and second night after booster he had chills. Five to six days later he went to the ER because his whole body had a rash, all over body was itching, heartbeat is very fast. Oxygen saturation was very low. He has hives all over his body. Company comment: This case concerns a 65-year-old male patient with no relevant medical history and concurrent administration of Influenza vaccine who experienced non-serious unexpected adverse event of special interest (AESI) tachycardia. The event occurred approximately 5-6 days after the booster dose of the mRNA-1273. Reportedly, the patient also had chills on the first and the second day following vaccination, as well as hives, rash, itching, low oxygen saturation. The patient visited ER due to the events. Rechallenge was not applicable since the event occurred after the 3rd dose so, no rechallenge was done and recurrence was not applicable.  The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This case concerns a 65-year-old male patient with no relevant medical history and concurrent administration of Influenza vaccine who experienced non-serious unexpected adverse event of special interest (AESI) tachycardia. The event occurred approximately 5-6 days after the booster dose of the mRNA-1273. Reportedly, the patient also had chills on the first and the second day following vaccination, as well as hives, rash, itching, low oxygen saturation. The patient visited ER due to the events. Rechallenge was not applicable since the event occurred after the 3rd dose so, no rechallenge was done and recurrence was not applicable.  The benefit-risk relationship of mRNA-1273 is not affected by this report.