COVID-19; A 4th dose of Moderna vaccine given 37 days before the 1st dose of Pfizer's COVID-19 vaccine treatment; This spontaneous case was reported by a patient and describes the occurrence of COVID-19 (COVID-19) and INTERCHANGE OF VACCINE PRODUCTS (A 4th dose of Moderna vaccine given 37 days before the 1st dose of Pfizer's COVID-19 vaccine treatment) in a 67-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 80777-0273-99 SCH O) for COVID-19 vaccination.     Concurrent medical conditions included Sulfonamide allergy.    On 05-Apr-2022, the patient received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced COVID-19 (COVID-19) and INTERCHANGE OF VACCINE PRODUCTS (A 4th dose of Moderna vaccine given 37 days before the 1st dose of Pfizer's COVID-19 vaccine treatment). At the time of the report, COVID-19 (COVID-19) and INTERCHANGE OF VACCINE PRODUCTS (A 4th dose of Moderna vaccine given 37 days before the 1st dose of Pfizer's COVID-19 vaccine treatment) outcome was unknown.            Patient received a 4th dose of mRNA-1273 vaccine on 5 April 2022. Patient also received Pfizer's COVID-19 vaccine on 12-May-2022 (Batch/Lot number-NDC 0069-1085-30) and last administered date was 16-May-2022. Pfizer's COVID-19 vaccine was indicated as a treatment for COVID-19. Patient reported scratchy throat, tired, & congested 10 days after receiving the 1st dose of Pfizer's COVID-19 vaccine treatment. Patient denied taking any medications or products within 2 weeks of starting COVID-19 treatment.  Company Comment: This spontaneous case concerns a 67-year-old, female patient, with no relevant medical history reported, who experienced an unexpected, non-serious AESI COVID-19 in association with a 4th dose of mRNA-1273 vaccine. Patient received 2 doses of Pfizer's COVID-19 vaccine, given at 4 days interval, as a treatment to the event COVID-19. Her vaccination with a 4th dose of mRNA-1273 vaccine occurred 37 days before she received the 1st dose of Pfizer's COVID-19 vaccine treatment. Patient reported scratchy throat, tired, & congested 10 days after receiving the 1st dose of Pfizer's COVID-19 vaccine treatment. Further details on the medical history, clinical course, diagnostics, and treatments were not reported. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.; Sender's Comments: This spontaneous case concerns a 67-year-old, female patient, with no relevant medical history reported, who experienced an unexpected, non-serious AESI COVID-19 in association with a 4th dose of mRNA-1273 vaccine. Patient received 2 doses of Pfizer's COVID-19 vaccine, given at 4 days interval, as a treatment to the event COVID-19. Her vaccination with a 4th dose of mRNA-1273 vaccine occurred 37 days before she received the 1st dose of Pfizer's COVID-19 vaccine treatment. Patient reported scratchy throat, tired, & congested 10 days after receiving the 1st dose of Pfizer's COVID-19 vaccine treatment. Further details on the medical history, clinical course, diagnostics, and treatments were not reported. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.