I received the Moderna booster, then 2 months later was noted on surveillance MRI of another local recurrence; Interchange of vaccine products; Revaccination with different COVID-19 vaccine; This spontaneous case was reported by a physician and describes the occurrence of MELANOMA RECURRENT (I received the Moderna booster, then 2 months later was noted on surveillance MRI of another local recurrence) in a 59-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 066F21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for an unknown indication.    Patient medical history, concomitant disease, risk factor included melanoma, s/p resection x2. Was treated with Inhibitors of the immune checkpoint inhibitor concomittantly The patient did not had any additional medical history, concomitant disease or risk factor.  There were no additional lab data/results available.  Concurrent medical conditions included Melanoma.   On 23-Nov-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .5 milliliter. On an unknown date, the patient received dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) 1 dosage form. On an unknown date, received dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced MELANOMA RECURRENT (I received the Moderna booster, then 2 months later was noted on surveillance MRI of another local recurrence) (seriousness criterion medically significant), INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine). On 21-Feb-2022, MELANOMA RECURRENT (I received the Moderna booster, then 2 months later was noted on surveillance MRI of another local recurrence) had resolved. At the time of the report, INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) and COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Biopsy: Inconclusive. On an unknown date, Magnetic resonance imaging: Inconclusive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No Concomitant medications were provided. Patient was  a physician and received two initial doses of Pfizer 2 months later, patient was found to had a local recurrence of melanoma. It was removed 6 months later. Patient received the Moderna booster, then 2 months later was noted on surveillance MRI of another local recurrence. Medication Details and reason for taking the medicine included surgical resection.  Company Comment: This spontaneous case of Interchange of vaccine products concerns a 59-year-old female patient, with relevant medical history of Melanoma, who experienced the unexpected serious (medically significant) event of Melanoma recurrent. The event occurred approximately 2 months after receiving the third dose of mRNA-1273 Vaccine. It was reported that patient received two initial doses of Pfizer. Two months later, patient was found to have a local recurrence of melanoma that was removed 6 months later. After booster dose of Moderna, patient was noted on surveillance MRI to have another local recurrence. Diagnostic tests - MRI and Biopsy were reported as inconclusive. Treatment included surgical resection. The outcome of the event was reported as resolved. The patient's medical history of Melanoma (with recurrence after Pfizer vaccination) remain as a confounder for the occurrence of the event. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.; Sender's Comments: This spontaneous case of Interchange of vaccine products concerns a 59-year-old female patient, with relevant medical history of Melanoma, who experienced the unexpected serious (medically significant) event of Melanoma recurrent. The event occurred approximately 2 months after receiving the third dose of mRNA-1273 Vaccine. It was reported that patient received two initial doses of Pfizer. Two months later, patient was found to have a local recurrence of melanoma that was removed 6 months later. After booster dose of Moderna, patient was noted on surveillance MRI to have another local recurrence. Diagnostic tests - MRI and Biopsy were reported as inconclusive. Treatment included surgical resection. The outcome of the event was reported as resolved. The patient's medical history of Melanoma (with recurrence after Pfizer vaccination) remain as a confounder for the occurrence of the event. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.