Positive antigen test on following negative antigen test; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Positive antigen test on following negative antigen test) in a 73-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 028A21A and 025A21A) for COVID-19 vaccination.    Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for an unknown indication.    Concurrent medical conditions included Sulfonamide allergy. Concomitant products included SUMATRIPTAN, MELATONIN, ASCORBIC ACID, TOCOPHERYL ACETATE, XANTOFYL, ZEAXANTHIN, ZINC (AREDS), TRAZODONE and VENLAFAXINE for an unknown indication.   On 01-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 29-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 29-Oct-2021, the patient received third dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) 1 dosage form. On 20-Apr-2022, received fourth dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) dosage was changed to 1 dosage form. On 25-May-2022, the patient experienced COVID-19 (Positive antigen test on following negative antigen test). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 25-May-2022 to 29-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Positive antigen test on following negative antigen test) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 01-Jun-2022, SARS-CoV-2 test: positive (Positive) Positive antigen test on following negative antigen test  (1-JUN-2022 07:00). On an unknown date, SARS-CoV-2 test: negative (Negative) negative antigen test.         Company comment: This is a spontaneous case concerning a 73-year-old female  patient with no reported relevant medical history, who experienced the non-serious unexpected event of COVID-19, more than 13 months after the administration of second dose of mRNA-1273 vaccine. Clinical course details were not provided. Patient was treated with Paxlovid. After 7 days starting paxlovid and following a negative antigen test, patient had a positive antigen test. After primary vaccination with mRNA-1273, patient received 2  doses of COVID-19 vaccination with TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE). The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.  On 1-JUN-2022 07:00, the patient experienced positive antigen test on following negative antigen test. No treatment medications was received for COVID-19 recurrent. Sender's Comments: Company comment: This is a spontaneous case concerning a 73-year-old female  patient with no reported relevant medical history, who experienced the non-serious unexpected event of COVID-19, more than 13 months after the administration of second dose of mRNA-1273 vaccine. Clinical course details were not provided. Patient was treated with Paxlovid. After 7 days starting paxlovid and following a negative antigen test, patient had a positive antigen test. After primary vaccination with mRNA-1273, patient received 2  doses of COVID-19 vaccination with TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE). The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.