Lose consciousness; Hit my head/ Head wound required 9 staples to close it; Had mild concussion; Caused me to fall hit my head; Sudden dizziness; This spontaneous case was reported by a patient and describes the occurrence of LOSS OF CONSCIOUSNESS (Lose consciousness) and HEAD INJURY (Hit my head/ Head wound required 9 staples to close it) in a 42-year-old female patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     Previously administered products included for Product used for unknown indication: Flu shot on 14-Oct-2023. Past adverse reactions to the above products included No adverse effect with Flu shot. Concurrent medical conditions included Asthma.    On 14-Oct-2023, the patient received dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (Intramuscular use) 1 dosage form. On 15-Oct-2023, the patient experienced FALL (Caused me to fall hit my head) and DIZZINESS (Sudden dizziness). On an unknown date, the patient experienced LOSS OF CONSCIOUSNESS (Lose consciousness) (seriousness criterion medically significant), HEAD INJURY (Hit my head/ Head wound required 9 staples to close it) (seriousness criterion medically significant) and CONCUSSION (Had mild concussion). The patient was treated with PARACETAMOL (TYLENOL) at an unspecified dose and frequency; KETOROLAC TROMETHAMINE (TORADOL) at an unspecified dose and frequency; LIDOCAINE at an unspecified dose and frequency and Wound care (9 staples to close it) for Head injury. At the time of the report, LOSS OF CONSCIOUSNESS (Lose consciousness), HEAD INJURY (Hit my head/ Head wound required 9 staples to close it) and CONCUSSION (Had mild concussion) outcome was unknown and FALL (Caused me to fall hit my head) and DIZZINESS (Sudden dizziness) was resolving.            Concomitant medication was not provided. Patient experienced sudden dizziness that caused her to fall and hit his head and lose consciousness. Head wound required 9 staples to close it and had mild concussion. She was given Tylenol and Toradol at hospital during treatment, along with lidocaine at injury site while wound was being closed. Company comment: This spontaneous case concerns a 42-year-old female patient, with no relevant medical history reported, who experienced the unexpected, serious (medically significant) events of loss of consciousness and head injury in context of SPIKEVAX 2023-2024 dose administration, which unknown dose of COVID-19 vaccination schedule. Latency cannot be calculated due to events exact date unknown, however, it can be concluded that both events happened on the next day after vaccination as the result of the reported fall. It was also reported that the patient was vaccinated on the same day with a flu vaccine, which can be considered as a confounder. The course of events was reported to start the next day after vaccination with sudden dizziness that caused patient's fall which resulted in head injury and loss of consciousness. Head wound required 9 staples to close it and the patient had mild concussion. Treatment included Tylenol and Toradol at hospital during treatment, along with lidocaine at injury site. No further clinical information or details about etiologic and diagnostic work up were provided for medical review. Events outcome was unknown at the time of the report. The benefit-risk relationship of SPIKEVAX 2023-2024 vaccine is not affected by this report. Events seriousness was assessed as medically significant.