anaphylactic reactions; This literature-study case was reported in a literature article and describes the occurrence of ANAPHYLACTIC REACTION (anaphylactic reactions) in a 46-year-old patient of an unknown gender who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.      Concurrent medical conditions included Asthma, Allergic rhinitis and Oral allergy syndrome.   On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced ANAPHYLACTIC REACTION (anaphylactic reactions) (seriousness criterion medically significant). At the time of the report, ANAPHYLACTIC REACTION (anaphylactic reactions) outcome was unknown. Possible    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Skin test: negative (Negative) Negative.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered ANAPHYLACTIC REACTION (anaphylactic reactions) to be possibly related.    Patient was presented with Generalized hives, chest tightness, abdominal pain, diarrhea, rhinorrhea, facial and eyelid swelling. Patient received and tolerated 2nd dose in high-risk clinic.  Confirmed anaphylaxis by Brighton Criteria - Leve12 Confirmed anaphylaxis by NIAAD criteria - Yes PEG Challenge result: Passed  No concomitant information were reported. Treatment information was not provided.  Company Comment: This case concerns a 46-year-old patient of unknown gender, with medical history of asthma, allergic rhinitis and oral allergy syndrome, who experienced the expected serious event of anaphylactic reaction. The event occurred on unknown date after the first dose of Moderna COVID-19 vaccine. The rechallenge was negative since the event did not reoccurred after the second dose (tolerated, administrated on high-risk vaccination clinic). The event was considered related to the vaccine per the reporter's assessment. The medical history of asthma, allergic rhinitis and oral allergy syndrome remain as confounders since they suggest an allergic background. The benefit-risk relationship of Moderna COVID-19 vaccine is not affected by this report.   This case was linked to MOD-2021-372464, MOD-2021-372465, MOD-2021-372466.   Most recent FOLLOW-UP information incorporated above includes: On 03-Nov-2021: Follow up received by safety on 04-Nov-2021 included an Email received from Team .; Sender's Comments: This case concerns a 46-year-old patient of unknown gender, with medical history of asthma, allergic rhinitis and oral allergy syndrome, who experienced the expected serious event of anaphylactic reaction. The event occurred on unknown date after the first dose of Moderna COVID-19 vaccine. The rechallenge was negative since the event did not reoccurred after the second dose (tolerated, administrated on high-risk vaccination clinic). The event was considered related to the vaccine per the reporter's assessment. The medical history of asthma, allergic rhinitis and oral allergy syndrome remain as confounders since they suggest an allergic background. The benefit-risk relationship of Moderna COVID-19 vaccine is not affected by this report.