allergic reaction to a new medication; felt her  brain may be swelling; sensory problems where she could barely put on clothing/hear phones; gait keeps changing; face became flushed; headache; face became flushed; itchy all over/generalized itch upper body and face/uncontrollable itch; felt like she was under water with a spacy like feeling; 10 minutes later due to her face was swelling; extreme hot all over her body; working memory issues; all food tasted the same; This spontaneous case was reported by a consumer (subsequently medically confirmed) and describes the occurrence of HYPERSENSITIVITY (allergic reaction to a new medication) in a 45-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 046A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Patient have history of drug metabolism issues.  Concurrent medical conditions included Mast cell activation syndrome since 2014. Concomitant products included GUAIFENESIN, AMFETAMINE ASPARTATE, AMFETAMINE SULFATE, DEXAMFETAMINE SACCHARATE, DEXAMFETAMINE SULFATE (ADDERALL), HYDROXYZINE, EPINEPHRINE (EPIPEN), DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]), KETOTIFEN FUMARATE (KETOTISIN), ZILEUTON, CROMOLYN SODIUM, AZELASTINE, LEVOCETIRIZINE and FAMOTIDINE (PEPCID AC) for an unknown indication.    On 20-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 20-Mar-2021, the patient experienced the first episode of FLUSHING (face became flushed), PRURITUS (itchy all over/generalized itch upper body and face/uncontrollable itch), HOT FLUSH (felt like she was under water with a spacy like feeling), SWELLING FACE (10 minutes later due to her face was swelling), FEELING HOT (extreme hot all over her body), MEMORY IMPAIRMENT (working memory issues), AGEUSIA (all food tasted the same), GAIT DISTURBANCE (gait keeps changing), the second episode of FLUSHING (face became flushed) and HEADACHE (headache). On 10-Apr-2021, the patient experienced SENSITIVE SKIN (sensory problems where she could barely put on clothing/hear phones). On 22-Apr-2021, the patient experienced BRAIN OEDEMA (felt her  brain may be swelling). On 12-May-2021, the patient experienced HYPERSENSITIVITY (allergic reaction to a new medication) (seriousness criterion hospitalization). The patient was hospitalized on 12-May-2021 due to HYPERSENSITIVITY. At the time of the report, HYPERSENSITIVITY (allergic reaction to a new medication), BRAIN OEDEMA (felt her  brain may be swelling), PRURITUS (itchy all over/generalized itch upper body and face/uncontrollable itch), HOT FLUSH (felt like she was under water with a spacy like feeling), SWELLING FACE (10 minutes later due to her face was swelling), FEELING HOT (extreme hot all over her body), MEMORY IMPAIRMENT (working memory issues), AGEUSIA (all food tasted the same), SENSITIVE SKIN (sensory problems where she could barely put on clothing/hear phones), GAIT DISTURBANCE (gait keeps changing), the last episode of FLUSHING (face became flushed) and HEADACHE (headache) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 22-Apr-2021, Magnetic resonance imaging: normal (normal) Normal.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown. Treatment include visit to ER/Urgent Care four times, Prednisone, Benadryl, Pepcid and Xolair. 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.