When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled; No adverse event; gave a patient a vaccine/Some went in and some did not go in; This spontaneous case was reported by a pharmacist and describes the occurrence of SYRINGE ISSUE (When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled), ACCIDENTAL UNDERDOSE (gave a patient a vaccine/Some went in and some did not go in) and NO ADVERSE EVENT (No adverse event) in an adult male patient who received mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) for COVID-19 prophylaxis.    The suspect product included Pre-filled Syringe injection for COVID-19 prophylaxis.    No Medical History information was reported.   On 30-Sep-2023, the patient received dose of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (unknown route) 1 dosage form. On an unknown date, the patient started Pre-filled Syringe (unknown route) at an unspecified dose. On 30-Sep-2023,  after starting mRNA-1273.815 (SPIKEVAX 2023-2024 PFS), the patient experienced ACCIDENTAL UNDERDOSE (gave a patient a vaccine/Some went in and some did not go in). On an unknown date, the patient experienced SYRINGE ISSUE (When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled) and NO ADVERSE EVENT (No adverse event). At the time of the report, SYRINGE ISSUE (When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled), ACCIDENTAL UNDERDOSE (gave a patient a vaccine/Some went in and some did not go in) and NO ADVERSE EVENT (No adverse event) outcome was unknown.        For mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (Unknown), the reporter considered NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessments were provided for SYRINGE ISSUE (When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled) and ACCIDENTAL UNDERDOSE (gave a patient a vaccine/Some went in and some did not go in).  For Pre-filled Syringe, the reporter considered NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessments were provided for SYRINGE ISSUE (When they gave patient a vaccine and tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled) and ACCIDENTAL UNDERDOSE (gave a patient a vaccine/Some went in and some did not go in).    No concomitant medication was reported.  Reportedly, they administered vaccine to patient and the tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled. Some went in and some did not go in. They attached the needle to the syringe and when they put the plunger in some of the medicine spewed out the tip of the syringe, not the needle.  Device Issue / Malfunction Details: tip of the vaccine that goes into the needle was malfunctioning. When they pressed the plunger, it spilled (Syringe Tip leaking).  The Device problem code for Spikevax syringe included, FDA code 1670, IMDRF code A23 which included Use of Device Problem.  The Spikevax syringe device was malfunctioned, and the type was.  No treatment information was provided.   Most recent FOLLOW-UP information incorporated above includes: On 04-Oct-2023: from subordinate duplicate case. On 18-Oct-2023: Upon internal review on 18-Oct-2023, it was identified that MOD-2023-743832 is potential duplicate case for MOD-2023-743674. Hence, the information of MOD-2023-743832 has been captured and merged into case MOD-2023-743674. Reporter email address updated, device details updated, new event (Syringe issue) added and event Device component malfunction deleted, and reference number added.