Parkinson's disease; Dementia due to Parkinson's disease; Interchange of vaccine products; Seizures; Fever; This spontaneous case was reported by a consumer and describes the occurrence of PARKINSON'S DISEASE (Parkinson's disease), DEMENTIA (Dementia due to Parkinson's disease) and SEIZURE (Seizures) in a 75-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 065K21A and 030H21B) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect products included non-company products CARBIDOPA, LEVODOPA (DUOPA) for Parkinson's disease and TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 vaccination.    The patient's past medical history included Alcohol use in 2012 and Arterial stent insertion NOS. Concurrent medical conditions included Penicillin allergy, Non-smoker and Parkinson's disease. Concomitant products included LORAZEPAM for Anxiety, QUETIAPINE FUMARATE (SEROQUEL) for Anxiety and Prophylaxis, PARACETAMOL (TYLENOL) for Pain, TRAZODONE for Prophylaxis, VENLAFAXINE, MIDODRINE, MACROGOL 3350 (MIRALAX), VITAMIN D2 and LANSOPRAZOLE (PREVACID) for an unknown indication.   On 16-Oct-2017, the patient started CARBIDOPA, LEVODOPA (DUOPA) (Percutaneous) at an unspecified dose. On 06-Feb-2021, the patient received first dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) 1 dosage form. On 27-Feb-2021, received second dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (Intramuscular) dosage was changed to 1 dosage form. On 12-Dec-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 03-May-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 04-May-2022, the patient experienced SEIZURE (Seizures) (seriousness criteria death and medically significant) and PYREXIA (Fever). On an unknown date, the patient experienced PARKINSON'S DISEASE (Parkinson's disease) (seriousness criteria death and medically significant), DEMENTIA (Dementia due to Parkinson's disease) (seriousness criteria death and medically significant) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products). The patient was treated with Hospice care for Parkinson's disease; Hospice care for Dementia; Hospice care for Seizure and Hospice care for Pyrexia. The patient died on 12-May-2022. The reported cause of death was parkinson's disease and dementia due to parkinson's disease. It is unknown if an autopsy was performed. At the time of death, PYREXIA (Fever) had not resolved and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine products) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Body temperature: 104.3 f 104.3 F.         Company Comment: This spontaneous case concerns a 75-year-old old male patient with concurrent condition of Parkinson's Disease and relevant medical history of Arterial stent insertion who experienced the fatal unexpected, serious (medically significant) adverse event of special interest of Seizure and fatal, unexpected (medically significant) events of Parkinson's disease and Dementia which occurred after receiving a dose of mRNA-1273 vaccine taken as fourth dose of COVID-19 immunization. He previously received mRNA-1273 approximately five months prior to the current dose but with no information on adverse event. Interchange of vaccine products is noted in this case as he received Pfizer BIONTECH COVID-19 vaccine as primary series of COVID-19 immunization. Patient has been taking several central nervous system medications and was admitted to hospice care 10 months prior to the events. Two days after the last dose of mRNA-1273 administration, he developed high grade fever (104.7 degrees Fahrenheit) and seizure. The clinical course was not provided but reported that patient died at home 8 days after the onset of seizure. Death occurred 9 days after second dose of mRNA-1273 vaccine. The cause of death was reported as Parkinson's disease and Dementia due to Parkinson's disease. It is unknown if an autopsy was performed. Dementia is a common manifestation of Parkinson's disease. Concomitant use of  Venflaxine and Trazodone and occurrence of high grade fever are confounders for the event Seizure. Advanced age, medical history and low body mass index are also considered confounders for the fatal outcome. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 75-year-old old male patient with concurrent condition of Parkinson's Disease and relevant medical history of Arterial stent insertion who experienced the fatal unexpected, serious (medically significant) adverse event of special interest of Seizure and fatal, unexpected (medically significant) events of Parkinson's disease and Dementia which occurred after receiving a dose of mRNA-1273 vaccine taken as fourth dose of COVID-19 immunization. He previously received mRNA-1273 approximately five months prior to the current dose but with no information on adverse event. Interchange of vaccine products is noted in this case as he received Pfizer BIONTECH COVID-19 vaccine as primary series of COVID-19 immunization. Patient has been taking several central nervous system medications and was admitted to hospice care 10 months prior to the events. Two days after the last dose of mRNA-1273 administration, he developed high grade fever (104.7 degrees Fahrenheit) and seizure. The clinical course was not provided but reported that patient died at home 8 days after the onset of seizure. Death occurred 9 days after second dose of mRNA-1273 vaccine. The cause of death was reported as Parkinson's disease and Dementia due to Parkinson's disease. It is unknown if an autopsy was performed. Dementia is a common manifestation of Parkinson's disease. Concomitant use of  Venflaxine and Trazodone and occurrence of high grade fever are confounders for the event Seizure. Advanced age, medical history and low body mass index are also considered confounders for the fatal outcome. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Reported Cause(s) of Death: Parkinson's disease; Dementia due to Parkinson's disease