sepsis; Multiple inflammation Syndrome/MISA; received a Covid diagnosis March 2023, and "still caught covid anyway "after his 3rd dose; This spontaneous case was reported by a consumer and describes the occurrence of SEPSIS (sepsis) and MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (Multiple inflammation Syndrome/MISA) in a 63-year-old male patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included SPIKEVAX NOS (SPIKEVAX NOS) for COVID-19 prophylaxis.    No Medical History information was reported.   On 15-Oct-2023, the patient received dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (unknown route) 1 dosage form. On an unknown date, the patient received third dose of SPIKEVAX NOS (SPIKEVAX NOS) (unknown route) 1 dosage form. In April 2023, the patient experienced SEPSIS (sepsis) (seriousness criteria hospitalization and medically significant). On an unknown date, the patient experienced MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (Multiple inflammation Syndrome/MISA) (seriousness criteria hospitalization and medically significant) and COVID-19 (received a Covid diagnosis March 2023, and "still caught covid anyway "after his 3rd dose). The patient was hospitalized on sometime in April 2023 due to SEPSIS. At the time of the report, SEPSIS (sepsis), MULTISYSTEM INFLAMMATORY SYNDROME IN ADULTS (Multiple inflammation Syndrome/MISA) and COVID-19 (received a Covid diagnosis March 2023, and "still caught covid anyway "after his 3rd dose) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, SARS-CoV-2 test: (Negative) 3 weeks after testing negative and Positive.     For mRNA-1273.815 (SPIKEVAX 2023-2024) (Unknown), the reporter did not provide any causality assessments. For SPIKEVAX NOS (SPIKEVAX NOS) (Unknown), the reporter did not provide any causality assessments.   Concomitant medication was not reported. A patient stated that they had only had Moderna vaccines and received a Covid diagnosis March 2023, and was still caught covid anyway after his 3rd dose and 3 weeks after testing negative, he was hospitalized for 4 days with Sepsis Apr2023. They suspect it was caused by MISA which was in children. Patient stated that he was never diagnosed with Multiple inflammation Syndrome, it was only suspected, so when he went to schedule his appointment on the pharmacy website, he noticed they mentioned multiple information syndromes in adults and found it weird.  Treatment medication was not reported.  Company comment:  This is a spontaneous case concerning a 63-year-old, male patient with no reported medical history, who experienced the unexpected serious (hospitalization and medically significant) events of Multisystem inflammatory syndrome in adults (AESI), sepsis and non-serious event of COVID-19. The events occurred after the administration of the dose of SPIKEVAX 2023-2024 vaccine, used as a third dose, and SPIKEVAX COVID-19 VACCINE NOS. However, latency could not be assessed due to lack of information. Due to sepsis, the patient was hospitalized for 4 days. Multisystem inflammatory syndrome in adults was suspected but it is unclear if it occurred while having sepsis and or COVID-19.  No further information on clinical course, investigations and treatment received was available in the report. The benefit-risk relationship of SPIKEVAX 2023-2024 Vaccine and SPIKEVAX COVID-19 VACCINE NOS are not affected by this report.   This case was linked to MOD-2021-169838 (Patient Link).; Reporter's Comments: