This spontaneous case was reported by a consumer and describes the occurrence of COVID-19 (Rebound of COVID symptoms/positive antigen home test, day 5 after completing Paxlovid course) in a 75-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 065KZ1A and 939902) for COVID-19 vaccination. Concurrent medical conditions included Blood pressure high, High cholesterol, Graves' disease, Drug allergy (Allergy to sulfur), Penicillin allergy, Seasonal allergy (seasonal allergies) and Food allergy (allergy to chocolate). Concomitant products included LEVOTHYROXINE SODIUM (SYNTHROID) from 06-Jan-1997 to an unknown date, NEBIVOLOL HYDROCHLORIDE (BYSTOLIC) from 10-Apr-2007 to an unknown date and HYDROCHLOROTHIAZIDE, VALSARTAN (VALSARTAN HCT) for an unknown indication. On 08-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 08-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 23-Aug-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 30-Mar-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 04-May-2022 at 8:00 PM, after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COVID-19 (Rebound of COVID symptoms/positive antigen home test, day 5 after completing Paxlovid course). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 04-May-2022 to 08-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Rebound of COVID symptoms/positive antigen home test, day 5 after completing Paxlovid course) had not resolved. DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 13-May-2022, SARS-CoV-2 test: positive (Positive) Positive. It was reported that the patient was taking other medications/products within 2 weeks of starting COVID-19 treatment. On 13-May-2022 at 22:00, the patient had rebound of COVID symptoms and positive antigen home test, day 5 after completing Paxlovid course. The device date was reported as 15-May-2022. Company comment: This spontaneous case concerns a 75-year-old female patient, with no reported relevant medical history, who experienced unexpected, non-serious, AESI of COVID-19, 2 months after receiving a dose of mRNA-1273 vaccine as a fourth dose. Dose 1 and Dose 2 were given with a 31-day interval. Third dose was given 6 months after the second dose and the fourth dose was given 7 months after the third dose. The patient experienced Rebound of COVID-19 symptoms, confirmed by positive home antigen test, 5 days after completing a 5-day course of Nirmatrelvir-Ritonavir (Paxlovid). The event had not resolved. The benefit-risk relationship of mRNA-1273 is not affected by this report. Sender's Comments: This spontaneous case concerns a 75-year-old female patient, with no reported relevant medical history, who experienced unexpected, non-serious, AESI of COVID-19, 2 months after receiving a dose of mRNA-1273 vaccine as a fourth dose. Dose 1 and Dose 2 were given with a 31-day interval. Third dose was given 6 months after the second dose and the fourth dose was given 7 months after the third dose. The patient experienced Rebound of COVID-19 symptoms, confirmed by positive home antigen test, 5 days after completing a 5-day course of Nirmatrelvir-Ritonavir (Paxlovid). The event had not resolved. The benefit-risk relationship of mRNA-1273 is not affected by this report.