no adverse event; they had a hard time pushing on the plunger. The plunger did not go down.; This spontaneous case was reported by a pharmacist and describes the occurrence of DEVICE ISSUE (they had a hard time pushing on the plunger. The plunger did not go down.) and NO ADVERSE EVENT (no adverse event) in an 89-year-old male patient who received mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (batch no. 3030535) for COVID-19 prophylaxis.    Co-suspect product included Pre-filled Syringe injection (batch no. 3030535) for COVID-19 prophylaxis.    Patient had no allergy to food, medicine or other product. It was unknown if patient had been tested/diagnosed with COVID-19.  Concurrent medical conditions included Heart disease, unspecified and Diabetes. Concomitant products included INFLUENZA VACCINE INACT SPLIT 3V (FLUZONE HIGH DOSE) for an unknown indication.   On 03-Oct-2023 at 11:07 AM, 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 03-Oct-2023 at 11:07 AM, the patient experienced DEVICE ISSUE (they had a hard time pushing on the plunger. The plunger did not go down.). On an unknown date, the patient experienced NO ADVERSE EVENT (no adverse event). At the time of the report, DEVICE ISSUE (they had a hard time pushing on the plunger. The plunger did not go down.) 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 assessment was provided for DEVICE ISSUE (they had a hard time pushing on the plunger. The plunger did not go down.).  For Pre-filled Syringe, the reporter considered NO ADVERSE EVENT (no adverse event) to be not related. No further causality assessment was provided for DEVICE ISSUE (they had a hard time pushing on the plunger. The plunger did not go down.).    Administration site for Fluzone was reported as "L". Patient weight was reported as 120 (units unspecified)  Pharmacist reports that they received the Spikevax PFS for adults and when they were injecting one, they had a hard time pushing on the plunger. The plunger did not go down. They had to withdraw the needle from the patient. The vaccine was about to inject patient on 03-Oct-2023 but was not administered since dosage would not come out of the PFS. They have received 5 boxes early in the morning of 03-Oct-2023. Afterwards, 3 boxes were tested and obtained similar results. The needle was a 25G x 1 inch drop safe brand and easy points. There was no visual appearance issue. All 5 boxes that we received that day went to the refrigerator. Freezer was set at -7.2 C. Fridge was set to 38.2 C. Treatment medication was not reported. The Device problem code for Spikevax syringe include which include Use of Partial Blockage. The Spikevax syringe device was malfunctioned, and the type was CIRM.  It was reported that for the Lot 3030535 not all pre-filled syringes were tested from the 3 boxes, but a couple from each box had the same issue. The pre-filled syringe was uncapped before administration to the patient.  For the thawing process the vial/box is taken out of the freezer, the box is labeled 30 days after wards to indicate when it is no longer usable. Thawing time for the PFS was the same as a vial. The pharmacy did not have the vial doses at the time of the incident. They had only PFS available. There were 3 boxes still in the pharmacy which were available for return.   Most recent FOLLOW-UP information incorporated above includes: On 05-Oct-2023: Live follow up received contains reference number added. On 05-Oct-2023: Live follow up received contains reference number added. On 23-Oct-2023: Significant follow-up received. Patient information, concomitant medication, event onset date and narrative were updated.