anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening; anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening; malaise; groin pain; brain frog; armpit pain/right axillary (armpit)pain; arthralgia; fever; This spontaneous case was reported by a patient and describes the occurrence of ANTEROGRADE AMNESIA (anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening) in a 56-year-old male patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) (batch no. ASKU) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product INFLUENZA VACCINE (FLU [INFLUENZA VACCINE]) for an unknown indication.    Patient did not report any medical history or condition. He had nothing that would be related to his reactions.    On 22-Sep-2023, the patient received sixth dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (unknown route) 1 dosage form and dose of INFLUENZA VACCINE (FLU [INFLUENZA VACCINE]) (unknown route) 1 dosage form. On 23-Sep-2023, the patient experienced ANTEROGRADE AMNESIA (anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening) (seriousness criterion medically significant), RETROGRADE AMNESIA (anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening), MALAISE (malaise), GROIN PAIN (groin pain), BRAIN FOG (brain frog), AXILLARY PAIN (armpit pain/right axillary (armpit)pain), ARTHRALGIA (arthralgia) and PYREXIA (fever). On 24-Sep-2023, ANTEROGRADE AMNESIA (anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening) and RETROGRADE AMNESIA (anterograde and retrograde amnesia/had no short-term memory. He can't remember that evening) had resolved. At the time of the report, MALAISE (malaise), GROIN PAIN (groin pain), BRAIN FOG (brain frog), AXILLARY PAIN (armpit pain/right axillary (armpit)pain), ARTHRALGIA (arthralgia) and PYREXIA (fever) had resolved.        For mRNA-1273.815 (SPIKEVAX 2023-2024) (Unknown), the reporter did not provide any causality assessments.   Concomitant product use was not provided by the reporter.  On Friday (22-Sep-2023) he received his 6th dose simultaneously with the Flu vaccine.   On Saturday (23-Sep-2023) 24 hours later that evening he had anterograde and retrograde amnesia. He had no short-term memory. He can't remember that evening. On Sunday (24-Sep-2023) everything was cleared up.   It was reported that everything started on the evening of (23-Sep-2023). The patient was lefty.   Treatment information was not provided.    Company Comment: This is a spontaneous case concerning a 56-year-old, male patient with no reported medical history, who experienced the serious (due to medically significant) unexpected event of Anterograde amnesia, among other non-serious events. The event occurred the following day after the sixth dose of SPIKEVAX 2023-2024; the patient received INFLUENZA VACCINE (FLU [INFLUENZA VACCINE] on the same day, and he had received 5 previous doses of mRNA-1273 vaccine (1 st dose on 7-Mar-2021, 2nd dose on 5-Apr-2021, 3rd dose on 27-Nov-2021, 4th dose on 15-Jul-2022 and 5th dose on 10-Nov-2022). The following day after vaccination, the patient experienced anterograde and retrograde amnesia, in the context of fever, malaise, brain frog, arthralgia, groin pain and right axillary (armpit) pain. He had no short-term memory. He could not remember that evening. He got both the vaccine and the flu vaccine in the right arm because he is a lefty. He stated he never had any reaction to any other vaccine except inflammatory reaction, fever, chills, myalgia, and arthralgia. This episode resolved the following day. The outcome of the event was reported as recovered. INFLUENZA VACCINE (FLU [INFLUENZA VACCINE] is a confounder for all the events. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to US-MODERNATX, INC.-MOD-2023-745286, US-MODERNATX, INC.-MOD-2023-745287 (E2B Linked Report).; Sender's Comments:  US-MODERNATX, INC.-MOD-2023-745287:Bivalent Case US-MODERNATX, INC.-MOD-2023-745286:Monovalent Dose