severe sepsis right leg; Initial information received on 18-Nov-2022 regarding an unsolicited valid serious courtesy case received from a other health professional  This case involves a 66 years old male patient who was diagnosed with severe sepsis-right leg after receiving Quadrivalent Influenza Vaccine [Fluzone Quadrivalent].  The patient's past medical history included Vasectomy in 1992. The patient's past medical treatment included loratadine [Claritin] from 1995 to 30-APR-2021 via oral route a ta dose of 10 mg when required (PRN). The patient's past vaccination(s) and family history were not provided. At the time of the event, the patient had ongoing Type 2 diabetes mellitus since May-2000 (takes 4 medications to control condition), Sleep apnoea syndrome since May-1995, Obesity since 2015 and Seasonal allergy since 1995.  Patient's concomitant medications included Semaglutide (Ozempic) for type 2 diabetes mellitus; Empagliflozin, Metformin ydrochloride (Synjardy) for type 2 diabetes mellitus; Simvastatin for prophylaxis; Insulin Glargine (Toujeo) for type 2 diabetes mellitus; Glimepiride for type 2 diabetes mellitus; Paracetamol (Tylenol Extra Strength) for pain in extremity and continuous positive airway pressure (CPAP) machine for sleep apnea via respiratory inhalation at 1 inhalation once a day (qd) since may-1995  On 03-Oct-2022, the patient received a  dose of suspect Quadrivalent Influenza Vaccine (strength, dose, formulation , batch number, expiry date not reported) via intramuscular route in right deltoid for influenza.  On 08-OCT-2022 the patient developed a serious event of severe sepsis (sepsis) (latency: 5 days) following the administration of Quadrivalent Influenza Vaccine. This event caused hospitalization of patient (hospitalization duration: 17 days). It was reported that on 20-Oct-2022 at 14:21 patient was contacted to get an update on right foot sprain and he informed that he was in the hospital for a deep tissue staph infection in right foot that his foot sprain was misdiagnosed by PCP. Per the patient, on 08Oct2022 right foot became red, swollen, blisters on top of foot appeared, and he went to urgent care and was directed to go straight to the emergency room (ER), where he was diagnosed with Staph infection and had a procedure to clean wound and drain on 09Oct2022. The patient was recovering well and improving daily. Getting intravenous (IV) antibiotics three times daily and was scheduled for a peripherally inserted central catheter (PICC) line to get outpatient IV antibiotic treatment. Upon follow-up on 31Oct2022, the patient stated that he was expecting to get discharged within a few days of PICC line placement. On 03Nov2022, the site received the hospital medical records and the principal investigator (PI) wanted to update the term to reflect hospital diagnosis of sepsis due to right leg cellulitis/fasciitis, present on admission complicated by methicillin resistant staphylococcus aureus (MSSA). The patient had diabetes mellitus type II with hyperglycemia A1c 7.3% uncontrolled at admission.  Relevant laboratory test results included: Glycosylated haemoglobin - On an unknown date: 7.3 %  Action taken: not applicable.  It was reported that the patient was hospitalized for the event.  At time of reporting, the outcome was Unknown for the event.  Seriousness Criteria: Medically significant, disability and life threatening for the event severe sepsis-right leg.; Sender's Comments: Sanofi company comment dated 24-Nov-2022:  This case involves a 66 year old male patient who was diagnosed with severe sepsis-right leg after receiving vaccine Influenza Vaccine. Patient's pre-existing conditions included Type 2 diabetes mellitus, Sleep apnea syndrome, Obesity and Seasonal allergies. Additional information regarding condition at the time of vaccination, concomitant disease or risk factor excluding other predisposing etiologies would be needed for complete assessment of the case. Based upon the reported information, the role of vaccine cannot be assessed.