Immediate hypersensitivity reaction; Interchange of vaccine products; Revaccination with different COVID-19 vaccine; This literature-non-study case was reported in a literature article and describes the occurrence of TYPE I HYPERSENSITIVITY (Immediate hypersensitivity reaction) in a 33-year-old female patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 prophylaxis.    Concurrent medical conditions included Allergic rhinitis and Food allergy.   On an unknown date, the patient received first dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form and second dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) .3 milliliter. On an unknown date, the patient experienced TYPE I HYPERSENSITIVITY (Immediate hypersensitivity reaction) (seriousness criterion medically significant), INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine). The patient was treated with EPINEPHRINE at an unspecified dose and frequency. At the time of the report, TYPE I HYPERSENSITIVITY (Immediate hypersensitivity reaction), INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 antibody test: 22,954 arbitrary unit per millilitre and 73.5 arbitrary unit per millilitre. On an unknown date, Tryptase: 2.8 microgram per litre.     The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown.   For mRNA-1273 (Spikevax) (Unknown), the reporter considered TYPE I HYPERSENSITIVITY (Immediate hypersensitivity reaction), INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) to be related.    No concomitant medications were reported.  Patient did not have history of anaphylaxis, COVID-19 infection and allergy to vaccine. Patient experience shortness of breath, swelling of tongue and face within 30 minutes after first dose and was also treated with an unspecified antihistamines and steroids. Vaccine excipient test was not performed for patient. The patient experienced an immediate hypersensitivity reaction (within 4 hours) to a first dose of Moderna vaccine.  Patient received the second dose of vaccine in incremental doses at 30-minute intervals to a cumulative dose of 0.3 mL. Patient was premedicated with a second-generation H1 antihistamine on the dayof vaccination, and patient was observed for 1 hour after the final vaccine dose. COVID-19 spike antibody levels were measured at least 2 weeks after the procedure  cumulative time for second dose was reported as 2.5 hours, It was reported that 0.05-0.10-0.15 mL of sequential dose of vaccine was administered to complete a cumulative dose of 0.3 mL, reactions during graded dosing were None.  Company Comment: This is a Literature-non-study case concerning a 33-year-old female patient, with relevant medical history of allergic rhinitis and food allergy, who experienced the unexpected and serious (due to medically significant) event of Type I hypersensitivity, which occurred within 30 minutes after the first dose of mRNA-1273 vaccine. Patient experienced shortness of breath, and tongue and face swelling. In the emergency department, she received treatment with epinephrine, antihistamines and steroids. Pre-desensitization SARS-CoV-2 spike IgG level was 73.5 AU/ml, post-desensitization was 22,954 AU/ml, and serum tryptase level was 2.8 ug/L. At the time of the report, event outcome was unknown. Medical history of allergic rhinitis and food allergy could be a confounder for the case. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.   This case was linked to US-MODERNATX, INC.-MOD-2022-655520, US-MODERNATX, INC.-MOD-2022-655522, US-MODERNATX, INC.-MOD-2022-655503.   Most recent FOLLOW-UP information incorporated above includes: On 06-Oct-2022: Live Follow up received by safety on 06-Oct-2022 has email with full text article received and contains significant information. Reporter information, literature information, laboratory data, product and event details updated.; Sender's Comments: This is a Literature-non-study case concerning a 33-year-old female patient, with relevant medical history of allergic rhinitis and food allergy, who experienced the unexpected and serious (due to medically significant) event of Type I hypersensitivity, which occurred within 30 minutes after the first dose of mRNA-1273 vaccine. Patient experienced shortness of breath, and tongue and face swelling. In the emergency department, she received treatment with epinephrine, antihistamines and steroids. Pre-desensitization SARS-CoV-2 spike IgG level was 73.5 AU/ml, post-desensitization was 22,954 AU/ml, and serum tryptase level was 2.8 ug/L. At the time of the report, event outcome was unknown. Medical history of allergic rhinitis and food allergy could be a confounder for the case. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report. US-MODERNATX, INC.-MOD-2022-655520:24 yr old female US-MODERNATX, INC.-MOD-2022-655522:35 yr old female US-MODERNATX, INC.-MOD-2022-655503:29 yr old female