Anaphylactic Reaction; Rapid Heart rate; Narrowing of throat; swelling of tongue; This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of ANAPHYLACTIC REACTION (Anaphylactic Reaction), HEART RATE INCREASED (Rapid Heart rate), THROAT TIGHTNESS (Narrowing of throat) and SWOLLEN TONGUE (swelling of tongue) in a 49-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 008B21A) for COVID-19 vaccination.     No medical history was provided by the reporter.  Concomitant products included LEVOTHYROXINE for an unknown indication.    On 06-Jul-2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 06-Jul-2021, the patient experienced ANAPHYLACTIC REACTION (Anaphylactic Reaction) (seriousness criteria medically significant and life threatening). 06-Jul-2021, the patient experienced HEART RATE INCREASED (Rapid Heart rate) (seriousness criterion medically significant), THROAT TIGHTNESS (Narrowing of throat) (seriousness criterion medically significant) and SWOLLEN TONGUE (swelling of tongue) (seriousness criterion medically significant). The patient was treated with DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]) (oral) for Adverse event, at a dose of 50 mg; EPINEPHRINE for Adverse event, at a dose of 0.3 mg; METHYLPREDNISOLONE SODIUM SUCCINATE (SOLUMEDROL) for Adverse event, at a dose of 125 mg; FAMOTIDINE (PEPCID [FAMOTIDINE]) for Adverse event, at an unspecified dose and frequency and PREDNISONE for Adverse event, at an unspecified dose and frequency. On 08-Jul-2021, ANAPHYLACTIC REACTION (Anaphylactic Reaction), HEART RATE INCREASED (Rapid Heart rate), THROAT TIGHTNESS (Narrowing of throat) and SWOLLEN TONGUE (swelling of tongue) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.       Additional concomitant medication included "MP thyroid." Within 12 minutes of receiving the vaccine,  the patient developed an anaphylactic reaction, with swelling of tongue, narrowing of the throat and a rapid heart rate. Oral diphenhydramine 50 mg and epinephrine injection 0.3mg was given to the patient by emergency medical technicians.  The patient was taken in an ambulance where she received methylprednisolone sodium succinate 125 mg.  She was taken to a local emergency room for treatment.  In the emergency room, she was given famotidine and then discharged after observation.   Approximately 12 hours later, the patient began to experience the same anaphylactic reaction again and was taken to another emergency room.  The patient was treated with intravenous diphenhydramine  and an epinephrine injection. She was observed in the emergency room then discharged with prescription medicine.   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.; 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.