Fainting spell; Strongly positive antigen test; Weakness after going to toilet; Extreme dizziness; Return of fever (99.5-99.9F); This spontaneous case was reported by a consumer and describes the occurrence of SYNCOPE (Fainting spell) in a  patient of an unknown age and gender who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 013H21B) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Anemia, Alpha thalassaemia and Drug allergy (Drug was not specified). Concomitant products included FAMOTIDINE from 13-May-2022 to an unknown date for an unknown indication.    On 30-Dec-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 26-May-2022, the patient experienced SYNCOPE (Fainting spell) (seriousness criterion medically significant), COVID-19 (Strongly positive antigen test), ASTHENIA (Weakness after going to toilet), DIZZINESS (Extreme dizziness) and PYREXIA (Return of fever (99.5-99.9F)). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 18-May-2022 to 22-May-2022 for COVID-19 treatment, at a dose of 1 dosage form. At the time of the report, SYNCOPE (Fainting spell), COVID-19 (Strongly positive antigen test), ASTHENIA (Weakness after going to toilet), DIZZINESS (Extreme dizziness) and PYREXIA (Return of fever (99.5-99.9F)) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 26-May-2022, Body temperature: 99.5 - 99.9 f (High) 99.5 - 99.9 F. On 26-May-2022, SARS-CoV-2 test: strongly positive antigen test. (Positive) Strongly positive antigen test..         The patient took other medications/products within 2 weeks of receiving COVID-19 treatment.  Patient stated return of fever (99.5--99.9F) on 26-May-2022 (d4 after stopping paxlovid, d10 post start of symptoms).  Patient went to ER for hydration. Patient received IV fluids as treatment for the adverse event.  CC: This spontaneous case concerns a patient of unknown age and gender, with a relevant history of anemia and alpha thalassemia, who experienced the unexpected non-serious adverse event of special interest COVID-19 and the serious (medically significant) event of Syncope, that occurred 147 days after receiving mRNA-1273 vaccine as third dose in the COVID-19 vaccination series. Patient stated return of fever (99.5--99.9F) on the 4th day after stopping Paxlovid and on the 10th day after initial occurrence of symptoms, and experienced extreme weakness, fainting spell and dizziness. Patient was brought to ER for hydration with IV fluids. Outcome of the event was reported as resolving. Patient completed 5 days of treatment with Paxlovid. Underlying  history of anemia and alpha thalassemia and the ongoing COVID-19 could be confounders for the events Syncope and COVID-19. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This spontaneous case concerns a patient of unknown age and gender, with a relevant history of anemia and alpha thalassemia, who experienced the unexpected non-serious adverse event of special interest COVID-19 and the serious (medically significant) event of Syncope, that occurred 147 days after receiving mRNA-1273 vaccine as third dose in the COVID-19 vaccination series. Patient stated return of fever (99.5--99.9F) on the 4th day after stopping Paxlovid and on the 10th day after initial occurrence of symptoms, and experienced extreme weakness, fainting spell and dizziness. Patient was brought to ER for hydration with IV fluids. Outcome of the event was reported as resolving. Patient completed 5 days of treatment with Paxlovid. Underlying  history of anemia and alpha thalassemia and the ongoing COVID-19 could be confounders for the events Syncope and COVID-19. The benefit-risk relationship of mRNA-1273 is not affected by this report.