Patient received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine, approximately 8 months prior to mRNA-1273 vaccination; Initial COVID-19 infection prior to COVID-19 treatment; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Initial COVID-19 infection prior to COVID-19 treatment) and INTERCHANGE OF VACCINE PRODUCTS (Patient received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine, approximately 8 months prior to mRNA-1273 vaccination) in a 39-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     Previously administered products included for Product used for unknown indication: Pfizer / BioNTech (Dose Number: 1 Batch/Lot No: Unknown. Not available/provided to reporter at the time of report completion) on 05-Mar-2021 and Pfizer / BioNTech (Dose Number: 2 Batch/Lot No: Unknown. Not available/provided to reporter at the time of report completion) on 26-Mar-2021. Past adverse reactions to the above products included No adverse event with Pfizer / BioNTech and Pfizer / BioNTech. Concurrent medical conditions included Asthma and Allergy.    On 06-Dec-2021, the patient received third 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 COVID-19 treatment). On an unknown date, the patient experienced INTERCHANGE OF VACCINE PRODUCTS (Patient received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine, approximately 8 months prior to mRNA-1273 vaccination). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 09-May-2022 to 14-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 COVID-19 treatment) had resolved and INTERCHANGE OF VACCINE PRODUCTS (Patient received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine, approximately 8 months prior to mRNA-1273 vaccination) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 14-May-2022, SARS-CoV-2 test: negative (Negative) Tested negative twice on final day of Paxlovid course. On 16-May-2022, SARS-CoV-2 test: negative (Negative) Negative. On 20-May-2022, SARS-CoV-2 test: positive (Positive) Positive. On 23-May-2022, SARS-CoV-2 test: positive (Positive) continued to test positive through today.         No concomitant medication was reported by reporter.  Patient did not take any Medications within 2 weeks of starting Paxlovid.  Device date was reported as 23-May-2022.  Company Comment:  This is a spontaneous case concerning a 39-year-old male patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, which occurred approximately 5 months after receiving a dose of mRNA-1273 as the third dose of COVID-19 vaccine. Patient had received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine with no reported adverse event, approximately 8 months prior to mRNA-1273 vaccination (Interchange of vaccine products). Patient was given a six-day-course of Paxlovid treatment and tested negative twice for COVID-19 after the treatment course. However, four days after the treatment with Paxlovid, patient noted new unspecified symptoms and anosmia then tested positive twice for COVID-19. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 39-year-old male patient with no relevant medical history reported, who experienced the unexpected non-serious adverse event of special interest COVID-19, which occurred approximately 5 months after receiving a dose of mRNA-1273 as the third dose of COVID-19 vaccine. Patient had received 2-dose primary series of Pfizer/BioNTech COVID-19 vaccine with no reported adverse event, approximately 8 months prior to mRNA-1273 vaccination (Interchange of vaccine products). Patient was given a six-day-course of Paxlovid treatment and tested negative twice for COVID-19 after the treatment course. However, four days after the treatment with Paxlovid, patient noted new unspecified symptoms and anosmia then tested positive twice for COVID-19. The benefit-risk relationship of mRNA-1273 is not affected by this report.