The plunger did not go down all the way while administering; he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half; No adverse event; This spontaneous case was reported by a pharmacist and describes the occurrence of DEVICE ISSUE (The plunger did not go down all the way while administering), CIRCUMSTANCE OR INFORMATION CAPABLE OF LEADING TO MEDICATION ERROR (he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half) and NO ADVERSE EVENT (No adverse event) in a patient of an unknown age and gender 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.   In October 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 an unknown date, the patient experienced DEVICE ISSUE (The plunger did not go down all the way while administering), CIRCUMSTANCE OR INFORMATION CAPABLE OF LEADING TO MEDICATION ERROR (he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half) and NO ADVERSE EVENT (No adverse event). At the time of the report, DEVICE ISSUE (The plunger did not go down all the way while administering), CIRCUMSTANCE OR INFORMATION CAPABLE OF LEADING TO MEDICATION ERROR (he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half) 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 ISSUE (The plunger did not go down all the way while administering) and CIRCUMSTANCE OR INFORMATION CAPABLE OF LEADING TO MEDICATION ERROR (he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half).  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 ISSUE (The plunger did not go down all the way while administering) and CIRCUMSTANCE OR INFORMATION CAPABLE OF LEADING TO MEDICATION ERROR (he was administering a shot and he thinks plunger did not go down all the way while administering, he didnot look but he thinks the plunger went down more than half).    Reporter need to report an issue with Spikevax syringe for which plunger did not go down all the way while administering. Reporter stated he did not look but the plunger went more than half. One patient was involved.  The Device problem code for Spikevax syringe include FDA code 2900, RA code A12 which includes Connection Problem. The Spikevax syringe device was malfunctioned and the type was CIRM.  The concomitant medication was not reported by reporter. The treatment medication was not reported by reporter.  QC Comment: The event cannot be further investigated since the consent for the Quality Team to follow up with the complaint was declined. As the batch number was not reported initially and no follow up can be performed, this event will be closed with no investigation.   Reporter did not allow further contact   Most recent FOLLOW-UP information incorporated above includes: On 17-Oct-2023: Closed PQC report received.