Patient received 3 doses of Pfizer/BioNTech COVID-19 vaccine prior to a dose of mRNA-1273 vaccine; Initial COVID-19 infection prior to Paxlovid treatment; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Initial COVID-19 infection prior to Paxlovid treatment) and INTERCHANGE OF VACCINE PRODUCTS (Patient received 3 doses of Pfizer/BioNTech COVID-19 vaccine prior to a dose of mRNA-1273 vaccine) in a 49-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     Previously administered products included for Drug use for unknown indication: Pfizer / BioNTech (Dose Number: 3, Batch/Lot No: Unknown), Pfizer / BioNTech (Dose Number: 1 Batch/Lot No: Unknown), Pfizer / BioNTech (Dose Number: 2 and Batch/Lot No: unknown). Past adverse reactions to the above products included No adverse event with Pfizer / BioNTech, Pfizer / BioNTech and Pfizer / BioNTech. Concurrent medical conditions included Relapsing polychondritis, Penicillin allergy, Allergy (Cecile allergy), Latex allergy and Fruit allergy (avocado). Concomitant products included ADALIMUMAB (HUMIRA) from an unknown date to 14-May-2022 and ROSUVASTATIN CALCIUM (CRESTOR) from an unknown date to 15-May-2022 for an unknown indication.    On 18-Jan-2022, the patient received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In May 2022, the patient experienced COVID-19 (Initial COVID-19 infection prior to Paxlovid treatment). On an unknown date, the patient experienced INTERCHANGE OF VACCINE PRODUCTS (Patient received 3 doses of Pfizer/BioNTech COVID-19 vaccine prior to a dose of mRNA-1273 vaccine). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 13-May-2022 to 15-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Initial COVID-19 infection prior to Paxlovid treatment) and INTERCHANGE OF VACCINE PRODUCTS (Patient received 3 doses of Pfizer/BioNTech COVID-19 vaccine prior to a dose of mRNA-1273 vaccine) outcome was unknown.            The patient's symptoms rebounded on day 9 that is on 25-May-2021.  No treatment was received for rebounded symptoms.  Company Comment:  This is a spontaneous case concerning a 49-year-old female patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, described as initial COVID-19 infection prior to Paxlovid treatment, which occurred approximately 4 months after receiving a dose of mRNA-1273 as the fourth dose of COVID-19 vaccine. Patient had received 3 doses of Pfizer/BioNTech COVID-19 vaccine with no reported adverse event, prior to a dose of mRNA-1273 vaccine (Interchange of vaccine products). Patient was treated with a three-day-course of Paxlovid for the initial COVID-19 infection. However, ten days after the treatment with Paxlovid, patient reported rebound of symptoms. Outcome of the event for the initial COVID-19 infection was unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 49-year-old female patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, described as initial COVID-19 infection prior to Paxlovid treatment, which occurred approximately 4 months after receiving a dose of mRNA-1273 as the fourth dose of COVID-19 vaccine. Patient had received 3 doses of Pfizer/BioNTech COVID-19 vaccine with no reported adverse event, prior to a dose of mRNA-1273 vaccine (Interchange of vaccine products). Patient was treated with a three-day-course of Paxlovid for the initial COVID-19 infection. However, ten days after the treatment with Paxlovid, patient reported rebound of symptoms. Outcome of the event for the initial COVID-19 infection was unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report.