feeling really tired; heart palpitation; hives which come back daily; sensation that "something there was swelling" (she could not tell) in the middle part of her right back; sensation that "something there was painful (she could not tell) in the middle part of her right bac; itching on the right side of her face; This spontaneous case was reported by a consumer and describes the occurrence of PALPITATIONS (heart palpitation) in a 47-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included G6PD deficiency (G6PD), Palpitation and Hives.    On 21-Dec-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 21-Dec-2021, the patient experienced PALPITATIONS (heart palpitation) (seriousness criterion medically significant), URTICARIA (hives which come back daily), SWELLING (sensation that "something there was swelling" (she could not tell) in the middle part of her right back), BACK PAIN (sensation that "something there was painful (she could not tell) in the middle part of her right bac) and PRURITUS (itching on the right side of her face). On 23-Dec-2021, the patient experienced FATIGUE (feeling really tired). At the time of the report, PALPITATIONS (heart palpitation), URTICARIA (hives which come back daily), SWELLING (sensation that "something there was swelling" (she could not tell) in the middle part of her right back), BACK PAIN (sensation that "something there was painful (she could not tell) in the middle part of her right bac), PRURITUS (itching on the right side of her face) and FATIGUE (feeling really tired) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 26-Dec-2021, Blood pressure measurement: 131/65 (abnormal) 131/65. On an unknown date, Heart rate: 91 (abnormal) 91 or sometimes 119.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       No concomitant product was provided. 4 days before the vaccine, patient had an environmental allergy test done on the same area (middle part of her back). Patient had a history of heart Palpitation in the past and was being worked up. Echocardiogram  was performed, but the results were not reported.  Patient reported she had another cardio appointment next month and they will "further study her heart" She states that she has hives which come back daily. And this was happening before she had the Moderna shot but this again recurred when she got the Moderna shot together with the palpitation. No medications were done and the itching and the palpitation but would still come and go. She was advised by her allergist to take Benadryl but she has G6PD and Benadryl is one medication that she should avoid.  Company comment: This spontaneous case concerns a 47-year-old female patient with a relevant medical history of Palpitation and Urticaria, who experienced the unexpected serious (medically significant) event of Palpitations and the unexpected non serious event of Urticaria after mRNA- 1273 vaccine. The onset of the event occurred on the day after the first dose of mRNA- 1273 vaccine. Heart rate was reported between 91 and 119bpm. Additionally, the patient experienced urticaria. Echocardiogram was performed, but the results were not reported. Cardiologic assessment was pending. Very limited information is available regarding medical assessment and diagnostic work-up. The patient reported Palpitations as a medically significant event, and is retained as such in compliance with a regulatory authority guideline on good pharmacovigilance practices. However, there is insufficient evidence to support this seriousness assessment from a clinical or regulatory standpoint. Previous history of Palpitations and Urticaria remain a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 47-year-old female patient with a relevant medical history of Palpitation and Urticaria, who experienced the unexpected serious (medically significant) event of Palpitations after mRNA- 1273 vaccine. The onset of the event occurred on the day after the first dose of mRNA- 1273 vaccine. Heart rate was reported between 91 and 119bpm. Additionally, the patient experienced urticaria. Echocardiogram was performed, but the results were not reported. Cardiologic assessment was pending. Very limited information is available regarding medical assessment and diagnostic work-up. The patient reported Palpitations as a medically significant event, and is retained as such in compliance with a regulatory authority guideline on good pharmacovigilance practices. However, there is insufficient evidence to support this seriousness assessment from a clinical or regulatory standpoint. Previous history of Palpitations and Urticaria remain a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.