Symptomatic breakthrough infection (positive rapid antigen COVID test); This spontaneous case was reported by a pharmacist and describes the occurrence of BREAKTHROUGH COVID-19 (Symptomatic breakthrough infection (positive rapid antigen COVID test)) in a 35-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 032f21a) for COVID-19 prophylaxis.     The patient had no medical history, concomitant disease or risk factor.     On 30-Oct-2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, the patient experienced BREAKTHROUGH COVID-19 (Symptomatic breakthrough infection (positive rapid antigen COVID test)). The patient was treated with ACETAMINOPHEN (oral) for Fever, at an unspecified dose and frequency; IBUPROFEN (oral) for Fever, at an unspecified dose and frequency; DEXTROMETHORPHAN HYDROBROMIDE, GUAIFENESIN (GUAIFENESIN/DEXTROMETHORPHAN) (oral) for Cough and Congestion nasal, at an unspecified dose and frequency and PSEUDOEPHEDRINE (oral) for Nasal congestion, at an unspecified dose and frequency. At the time of the report, BREAKTHROUGH COVID-19 (Symptomatic breakthrough infection (positive rapid antigen COVID test)) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: (Positive) Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No concomitant product use was reported.   The patient administered booster dose.  The patient did not experience any additional symptoms/events.  Company comment: This spontaneous case concerns a 35-year-old female patient, with no reported medical history, who experienced the unexpected non-serious AESI of Breakthrough COVID-19 (reported as Symptomatic breakthrough infection (positive rapid antigen COVID test)) after receiving the mRNA-1273 vaccine as booster dose. The onset date of event was not provided. Patient had high grade fever, cough, and nasal congestion, and was treated with Acetaminophen, Ibuprofen, Dextromethorphan hydrobromide, Guaifenesin, and Pseudoephedrine. On an unknown date, SARS-CoV-2 test was reported positive. Clinical course was not reported. The outcome of event was reported as resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report.   Reporter did not allow further contact; Sender's Comments: This spontaneous case concerns a 35-year-old female patient, with no reported medical history, who experienced the unexpected non-serious AESI of Breakthrough COVID-19 (reported as Symptomatic breakthrough infection (positive rapid antigen COVID test)) after receiving the mRNA-1273 vaccine as booster dose. The onset date of event was not provided. Patient had high grade fever, cough, and nasal congestion, and was treated with Acetaminophen, Ibuprofen, Dextromethorphan hydrobromide, Guaifenesin, and Pseudoephedrine. On an unknown date, SARS-CoV-2 test was reported positive. Clinical course was not reported. The outcome of event was reported as resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report.