Rebound of symptoms; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (Rebound of symptoms) in a 46-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 026L21B, 030B21A, 011M20A and 025J20A) for COVID-19 vaccination.     Concurrent medical conditions included Crohn's disease and Drug allergy (Name of Drug Reported as no). Concomitant products included USTEKINUMAB (STELARA) from 18-Apr-2022 to an unknown date and ESCITALOPRAM OXALATE (LEXAPRO) for an unknown indication.   On 07-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 05-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 04-Sep-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 16-Mar-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 15-May-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COVID-19 (Rebound of symptoms). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 15-May-2022 to 19-May-2022 for COVID-19 treatment, at an unspecified dose and frequency. At the time of the report, COVID-19 (Rebound of symptoms) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 15-May-2022, SARS-CoV-2 test: positive (Positive) Positive. On 23-May-2022, SARS-CoV-2 test: positive (Positive) Positive. On 25-May-2022, SARS-CoV-2 test: positive (Positive) Tested dtrong positive again.         The event reported was Paxlovid rebound. Started Paxlovid on same day as positive test and start of symptoms, 15-May-2022. Finished on 19-May-2022, after completing full 5 day course. Felt better 20-May-2022 and 21-May-2022. Patient was tested almost negative (very faint line) on 23-May-2022. On 25-May-2022, patient was tested strong positive again. Symptoms were similar to day one: sore throat, post-nasal drip, extreme fatigue, aches, slight cough with Device Date as 26-May-2022.  Treatment information was not provided.  Company comment: This is a spontaneous case concerning a 46-year-old, female patient with no relevant medical history and with vaccine history of receiving first, second and third dose of mRNA-1273 vaccine with appropriate dosage interval of 29 days for the first and second dose. Patient experienced the unexpected non-serious AESI event of Covid-19. The event occurred approximately 60 days after the fourth dose of mRNA-1273 vaccine administration. The event was described as, approximately 60 days after the fourth dose of mRNA-1273 vaccine administration, patient experienced sore throat, post-nasal drip, fatigue, aches and cough. On the same day, patient was tested positive, and patient took Nirmatrelvir + Ritonavir (Paxlovid) for treatment of Covid-19. Patient completed the full 5-day course and felt better. Approximately 4 days after the last dose of Nirmatrelvir + Ritonavir (Paxlovid), patient tested with almost negative very faint line. However approximately 6 days after the last dose of  Nirmatrelvir + Ritonavir (Paxlovid), patient tested strong positive again and experienced symptoms similar to day one. No other information surrounding the event was reported. The outcome of the event was reported as not resolved. The current Covid-19 pandemic remain confounder for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 46-year-old, female patient with no relevant medical history and with vaccine history of receiving first, second and third dose of mRNA-1273 vaccine with appropriate dosage interval of 29 days for the first and second dose. Patient experienced the unexpected non-serious AESI event of Covid-19. The event occurred approximately 60 days after the fourth dose of mRNA-1273 vaccine administration. The event was described as, approximately 60 days after the fourth dose of mRNA-1273 vaccine administration, patient experienced sore throat, post-nasal drip, fatigue, aches and cough. On the same day, patient was tested positive, and patient took Nirmatrelvir + Ritonavir (Paxlovid) for treatment of Covid-19. Patient completed the full 5-day course and felt better. Approximately 4 days after the last dose of  Nirmatrelvir + Ritonavir (Paxlovid), patient tested with almost negative very faint line. However approximately 6 days after the last dose of  Nirmatrelvir + Ritonavir (Paxlovid), patient tested strong positive again and experienced symptoms similar to day one. No other information surrounding the event was reported. The outcome of the event was reported as not resolved. The current Covid-19 pandemic remain confounder for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.