No adverse event; Needle didn't lock properly and the vaccine leaked out of the syringe; The vaccine leaked out of the syringe; This spontaneous case was reported by a pharmacist and describes the occurrence of DEVICE CONNECTION ISSUE (Needle didn't lock properly and the vaccine leaked out of the syringe), SYRINGE ISSUE (The vaccine leaked out of the syringe) and NO ADVERSE EVENT (No adverse event) in a male patient of an unknown age who received mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (batch no. 3030535) for COVID-19 prophylaxis.    Suspect product included Pre-filled Syringe injection (batch no. 3030535) for COVID-19 prophylaxis.    Previously administered products included for Product used for unknown indication: Influenza. Past adverse reactions to the above products included No adverse event with Influenza.   On 06-Oct-2023, the patient received fourth 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 06-Oct-2023, the patient experienced DEVICE CONNECTION ISSUE (Needle didn't lock properly and the vaccine leaked out of the syringe) and SYRINGE ISSUE (The vaccine leaked out of the syringe). On an unknown date, the patient experienced NO ADVERSE EVENT (No adverse event). At the time of the report, DEVICE CONNECTION ISSUE (Needle didn't lock properly and the vaccine leaked out of the syringe), SYRINGE ISSUE (The vaccine leaked out of the syringe) 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 DEVICE CONNECTION ISSUE (Needle didn't lock properly and the vaccine leaked out of the syringe) and SYRINGE ISSUE (The vaccine leaked out of the syringe).  For Pre-filled Syringe, the reporter considered NO ADVERSE EVENT (No adverse event) to be not related. No further causality assessments were provided for DEVICE CONNECTION ISSUE (Needle didn't lock properly and the vaccine leaked out of the syringe) and SYRINGE ISSUE (The vaccine leaked out of the syringe).    No concomitant medications were reported.  When the dose went to be administered the needle didn't lock properly and the vaccine leaked out of the syringe and onto the patient's arm. Physician stated that upon inspection and attaching the needle, it looked loose. The physician administering the dose was wearing gloves so there was no occupational exposure. They repeated the dose for the patient. No adverse effects occurred as a result of this vaccine administration.  The Device problem code for Spikevax syringe include FDA code 2900 and 1250, IMDRF code A12 and A050401 which include use of connection problem and fluid leak. The Spikevax syringe device was malfunctioned, and the type was CIRM.  No treatment medications were provided.  Rationale for no investigation: On 06Oct2023, upon prepping the dose during a vaccination clinic, they put a BD Safety Glide needle on the syringe. When the dose went to be administered the needle didn't lock properly and the vaccine leaked out of the syringe and onto the patient's arm. HCP states that upon inspection and attaching the needle, it looked loose. Follow up with the reporter was performed and the reporter stated that the needle was not loose, it was fully locked down. The reporter stated that the sample was disposed of as it was used for administration. Reporter did not observe a defect prior to administration; however, during administration the reporter stated the needle was loose. After an evaluation of the product quality impact and complaint trend analysis, it was determined that the Syringe/Rubber Tip & Rigid Cap threading issues has a minor severity per FRM-0762 and no lot specific trend was identified. A 3-sig deviation limit could not be established as the mean is too low to determine the 3-sig deviation limit as this is the 1st PQC received for CMO batch number 3030535 for Syringe/Rubber Tip Cap& Rigid Cap threading issues. The PQC was identified as threading issues as there was no leakage from the syringe until administration once the needle was applied. No further investigation is recommended.  Most recent FOLLOW-UP information incorporated above includes: On 10-Oct-2023: Live follow-up received contains reference numbers added. On 19-Oct-2023: Follow-up received contains non-significant information. On 16-Nov-2023: Follow-up information received included added PQC closed investigation report.