Rebound COVID-19 and symptoms/s positive both times; This spontaneous case was reported by an other health care professional and describes the occurrence of COVID-19 (Rebound COVID-19 and symptoms/s positive both times) in a 71-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 002MZ1A/00ZMZIA) for COVID-19 vaccination.     Previously administered products included for COVID-19 vaccination: Pfizer COVID-19 Vaccine (COVID-19 Vaccine: Dose 1, Manufacturer: Pfizer, LOT: EL9261) on 08-Feb-2021, Pfizer COVID-19 Vaccine (COVID-19 Vaccine: Dose 2, Manufacturer: Pfizer, LOT: EN6202) on 01-Mar-2021, Pfizer COVID-19 Vaccine (COVID-19 Vaccine: Dose 3, Manufacturer: Pfizer and LOT: FC3182) on 26-Sep-2021. Past adverse reactions to the above products included No adverse event with Pfizer COVID-19 Vaccine, Pfizer COVID-19 Vaccine and Pfizer COVID-19 Vaccine.    On 06-Apr-2022, the patient received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 18-May-2022, the patient experienced COVID-19 (Rebound COVID-19 and symptoms/s positive both times) (seriousness criterion medically significant). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 19-May-2022 to 23-May-2022 for COVID-19, at an unspecified dose and frequency. At the time of the report, COVID-19 (Rebound COVID-19 and symptoms/s positive both times) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 27-May-2022, SARS-CoV-2 test: positive (Positive) Result: Positive; Unit: Not Provided. On 31-May-2022, SARS-CoV-2 test: positive (Positive) Result: Positive; Unit: Not Provided.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   On 06-Apr-2022 she took Moderna COVID-19 Vaccine Dose 4, LOT: 00ZMZIA or 002MZIA, but thought 00ZMZIA or 00ZMZ1A. All vaccination information was provided from patient's record card.  She was not admitted on 18-May-2022 - positive COVID-19 at home. On 19-May-2022 started Paxlovid She took 5 days course of Paxlovid Symptoms quickly abated Then it wasn't even a couple days after stopped taking Paxlovid, she felt symptoms were coming back definitely was on day 5 of symptoms Still positive for COVID-19 and back in isolation had no scary symptoms ,had stuffy/runny nose, headache, and off-on sore throat. better than 4-5 days ago. It was nothing more than an upper respiratory head cold. She read in the last few days that Pfizer continued to say it was very low and they were calling it rebound COVID-19. Knew when the Paxlovid studies were done it was the delta variant, which was different. She had Pfizer vaccines two doses and been boosted twice. She was upset. Disappointed because she already did isolation. She should have gone and stayed the course of COVID-19 without medicine. She should not have taken Paxlovid. Emergency Room visit on 19-May-2022, but not admitted to hospital Physician Office. There were no predisposing factors. No culture was performed. Rebound COVID-19 and symptoms improved a little, but not a lot COVID-19 test remained positive entire time, tested twice, 27-May-2022 and 31-May-2022. a pain in the neck Clarified symptoms as stuffy/runny nose, headache, off-on sore throat, sinuses did not feel quite as bad. At first, had pressure and pain in the sinuses. Treatment was none, Paxlovid discarded the product Dose, standard, normal dose, it was 500/something else but she was not sure. Took it twelve hours apart If she wouldn't have taken Paxlovid, she would have been over it at this time and not experienced it twice.  AgencyCommunication: PC filed. There was a product complaint to report.  Company Comment: This spontaneous case concerns a 71-year-old female patient with history of interchange of vaccine products, who experienced the unexpected serious (medically significant) AESI of Covid-19, 42 days after receiving mRNA-1273 vaccine as 4th dose. She was tested positive for SARS-CoV-2 test and was treated with Paxlovid (Nirmatrelvir + Ritonavir) for five days. Two days later she had rebound symptoms and tested positive again and was diagnosed as rebound Covid-19. The outcome was reported as resolving. Details of symptoms, start date, clinical course, investigation reports and further treatment details were not provided. Six months prior to the Moderna vaccine, the patient had taken three doses of Pfizer COVID-19 Vaccine. Elderly age of the patient could be a risk factor. The current pandemic situation of Covid-19 could be a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 71-year-old female patient with history of interchange of vaccine products, who experienced the unexpected serious (medically significant) AESI of Covid-19, 42 days after receiving mRNA-1273 vaccine as 4th dose. She was tested positive for SARS-CoV-2 test and was treated with Paxlovid (Nirmatrelvir + Ritonavir) for five days. Two days later she had rebound symptoms and tested positive again and was diagnosed as rebound Covid-19. The outcome was reported as resolving. Details of symptoms, start date, clinical course, investigation reports and further treatment details were not provided. Six months prior to the Moderna vaccine, the patient had taken three doses of Pfizer COVID-19 Vaccine. Elderly age of the patient could be a risk factor. The current pandemic situation of Covid-19 could be a confounder. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.