Covid rebound - symptoms returned and antiGen showing positive for Covid on day 18/Fever originally went away on day 3; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Covid rebound - symptoms returned and antiGen showing positive for Covid on day 18/Fever originally went away on day 3) in a 43-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 034721A, 044A21A and 023A21A) for COVID-19 vaccination.     Concurrent medical conditions included Drug allergy (Name of drug was not reported). Concomitant products included SEMAGLUTIDE (OZEMPIC) from 23-Apr-2022 to an unknown date and FEXOFENADINE from 01-Jan-2022 to an unknown date for an unknown indication.   On 09-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 06-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 07-Dec-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced COVID-19 (Covid rebound - symptoms returned and antiGen showing positive for Covid on day 18/Fever originally went away on day 3). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 14-May-2022 to 19-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Covid rebound - symptoms returned and antiGen showing positive for Covid on day 18/Fever originally went away on day 3) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: negative (Negative) Negative after day 10 and positive (Positive) Positive for Covid on day 18..         Covid rebound - symptoms returned and antiGen showing positive for Covid on day 18. Fever originally went away on day 3 and AntiGen showed negative after day 10.  Device date was reported as 31-May-2022.  Company comment.  This spontaneous case concerns a 43  year  old, male patient with no medical history reported, who experienced the unexpected, non  serious AESI of COVID - 19. The event occurred approximately 5 months after the administration of the third dose of mRNA-1273 vaccine. The report stated that the patient experienced COVID  19 and received 5 days of treatment with Paxlovid. She mentioned that fever originally went away on day 3, and she had a Covid rebound since her symptoms returned and antigen was positive for Covid on day 18. No further details were provided for medical review. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 43  year  old, male patient with no medical history reported, who experienced the unexpected, non  serious AESI of COVID - 19. The event occurred approximately 5 months after the administration of the third dose of mRNA-1273 vaccine. The report stated that the patient experienced COVID  19 and received 5 days of treatment with Paxlovid. She mentioned that fever originally went away on day 3, and she had a Covid rebound since her symptoms returned and antigen was positive for Covid on day 18. No further details were provided for medical review. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.