Tested positive for Covid/ Tested positive in antigen test again after treatment/ Had the rebound effect; Interchange of vaccine products; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Tested positive for Covid/ Tested positive in antigen test again after treatment/ Had the rebound effect) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) in a 58-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 005C21A) for COVID-19 vaccination.     Previously administered products included for Product used for unknown indication: PFIZER BIONTECH COVID-19 VACCINE (Dose Number: 1 Batch/Lot No: EP7533 Location of injection: Arm Left) on 31-Mar-2021 and PFIZER BIONTECH COVID-19 VACCINE (Dose Number: 2 Batch/Lot No: EN5318 Location of injection: Arm Right) on 22-Apr-2021. Past adverse reactions to the above products included No adverse event with PFIZER BIONTECH COVID-19 VACCINE and PFIZER BIONTECH COVID-19 VACCINE. Concurrent medical conditions included Hypertension, Gout, High cholesterol and Allergic reaction to analgesics. Concomitant products included ROSUVASTATIN CALCIUM (CRESTOR) for High cholesterol, LOSARTAN from 01-Feb-2022 to an unknown date and ALLOPURINOL from 02-Jan-2019 to an unknown date for an unknown indication.    On 17-Dec-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 17-Dec-2021, the patient experienced INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products). On 10-May-2022, the patient experienced COVID-19 (Tested positive for Covid/ Tested positive in antigen test again after treatment/ Had the rebound effect). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 11-May-2022 to 15-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Tested positive for Covid/ Tested positive in antigen test again after treatment/ Had the rebound effect) had not resolved and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 10-May-2022, SARS-CoV-2 test: positive (Positive) Positive. On 22-May-2022, SARS-CoV-2 test: positive (Positive) Positive.         The patient was taking other medications/products within 2 weeks of starting COVID-19 treatment. The patient was tested positive for Covid 05 May, began Plaxlovid on 11 May to 15 May. After treatment of Paxlovid symptoms got resolved in 1-2 days. Patient was good for several, attended work at office and cut the lawn- all great. On 20-May-2022 or 21-May-2022, the patient had same symptoms, runny nose, congestion. Tested positive in antigen test on 22-May-2022. He was suspended Crestor for high cholesterol when taking Plaxovid. It was the rebound effect. Device Date was 23-May-2022.  Company comment: This spontaneous case concerns a 59 year old male patient, with no relevant medical history, who experienced the unexpected non serious AESI of COVID-19, about 4 months and 23 days after receiving the third dose of mRNA-1273 vaccine in the COVID-19 vaccination series. Additionally, Interchange of vaccine products was noted. The patient received the previous two doses with Pfizer vaccine, the last dose being given about 7 months prior to mRNA-1273 vaccine, with no reported adverse events. The patient tested positive for COVID-19 and started taking Paxlovid for 5 days after which he improved symptomatically. However, he got the symptoms back and tested positive for COVID-19, about 6 days later. The event was not resolved. The ongoing COVID-19 pandemic could be a risk factor for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 25-May-2022: Non significant follow up received Other Manufacturer number updated; Sender's Comments: This spontaneous case concerns a 59 year old male patient, with no relevant medical history, who experienced the unexpected non serious AESI of COVID-19, about 4 months and 23 days after receiving the third dose of mRNA-1273 vaccine in the COVID-19 vaccination series. Additionally, Interchange of vaccine products was noted. The patient received the previous two doses with Pfizer vaccine, the last dose being given about 7 months prior to mRNA-1273 vaccine, with no reported adverse events.The patient tested positive for COVID-19 and started taking Paxlovid for 5 days after which he improved symptomatically. However, he got the symptoms back and tested positive for COVID-19, about 6 days later. The event was not resolved. The ongoing COVID-19 pandemic could be a risk factor for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.