COVID-19; Interchange of Vaccine Products; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (COVID-19) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of Vaccine Products) in a 61-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 069F21A) for COVID-19 vaccination.     Previously administered products included for Product used for unknown indication: Pfizer / BioNTech (Dose Number: 1, Batch/Lot No: ER8737, Location of injection: Arm Left) on 05-Apr-2021, Pfizer / BioNTech (Dose Number: 2, Batch/Lot No: ER8735 and Location of injection: Arm Left) on 26-Apr-2021. Past adverse reactions to the above products included No adverse event with Pfizer / BioNTech and Pfizer / BioNTech. Concurrent medical conditions included Allergy (Allergy of unspecified drug). Concomitant products included ESCITALOPRAM OXALATE (LEXAPRO) and CETIRIZINE HYDROCHLORIDE, PSEUDOEPHEDRINE HYDROCHLORIDE (ZYRTEC-D) for an unknown indication.    On 16-Nov-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced COVID-19 (COVID-19) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of Vaccine Products). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 17-May-2022 to 22-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (COVID-19) had resolved and INTERCHANGE OF VACCINE PRODUCTS (Interchange of Vaccine Products) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 30-May-2022, SARS-CoV-2 test: positive (Positive) tested positive for COVID 8 days after finishing Paxlovid regiment. On an unknown date, SARS-CoV-2 test: positive (Positive) positive and negative (Negative) negative.         On 30-May-2022, COVID symptoms of the patient was returned. The patient did not receive any treatment for returned COVID symptoms.  Company Comment: This spontaneous case concerns a 61 year old female patient initially vaccinated with two doses of Covid 19 vaccine Pfizer with no reported adverse events, who experienced non-serious , unexpected, AESI of Covid 19 which occurred on an unknown date post vaccination with the third dose of mRNA-1273 vaccine. It was reported that this patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 17-May-2022 to 22-May-2022 for COVID-19, at an unspecified dose and frequency.  However she reported that her COVID Symptoms returned and she  tested positive for COVID 8 days after finishing Paxlovid regimen and receiving a negative test. Other details surrounding the events like other treatment information , if there were other laboratories/diagnostic procedures or any medical consult was done were not reported. Outcome of the event was reported as resolved. Event of interchange of vaccine products also occurred.  The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report.; Sender's Comments: This spontaneous case concerns a 61 year old female patient initially vaccinated with two doses of Covid 19 vaccine Pfizer with no reported adverse events, who experienced non-serious , unexpected, AESI of Covid 19 which occurred on an unknown date post vaccination with the third dose of mRNA-1273 vaccine. It was reported that this patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 17-May-2022 to 22-May-2022 for COVID-19, at an unspecified dose and frequency.  However she reported that her COVID Symptoms returned and she  tested positive for COVID 8 days after finishing Paxlovid regimen and receiving a negative test. Other details surrounding the events like other treatment information , if there were other laboratories/diagnostic procedures or any medical consult was done were not reported. Outcome of the event was reported as resolved. Event of interchange of vaccine products also occurred.  The benefit -risk relationship of mRNA -1273 ( Moderna Covid 19 Vaccine) is not affected by this report.