as soon as we tried to press the medication out, all of the liquid leaked from the Luer lock. It seems the luer lock (slip tip) is defective in this prefilled syringe; Prefilled syringe for PCV20 malfunctioned, causing all most of all of the medication to leak on the patient's arm; as soon as we tried to press the medication out, all of the liquid leaked from the Luer lock. It seems the luer lock (slip tip) is defective in this prefilled syringe; Prefilled syringe for PCV20 malfunctioned, causing all most of all of the medication to leak on the patient's arm; Prefilled syringe for PCV20 malfunctioned, causing all most of all of the medication to leak on the patient's arm; sore arm; This is a spontaneous report received from a contactable reporter (Consumer or other non HCP).  A 69-year-old female patient (not pregnant) received pneumococcal 20-valent conjugate vaccine (diphtheria CRM197 protein) (PREVNAR 20), on 20Apr2023 at 11:30 as dose number unknown, single (Lot number: GN1897, Expiration Date: Aug2024) at the age of 69 years intramuscular, in right deltoid for immunisation, pneumococcal immunisation. The patient had no relevant medical history. There were no concomitant medications. The following information was reported: DEVICE MALFUNCTION (non-serious), ACCIDENTAL EXPOSURE TO PRODUCT (non-serious), EXPOSURE VIA SKIN CONTACT (non-serious) all with onset 20Apr2023, outcome "unknown" and all described as "Prefilled syringe for PCV20 malfunctioned, causing all most of all of the medication to leak on the patient's arm"; DEVICE LEAKAGE (non-serious), POOR QUALITY DEVICE USED (non-serious) all with onset 20Apr2023, outcome "unknown" and all described as "as soon as we tried to press the medication out, all of the liquid leaked from the Luer lock. It seems the luer lock (slip tip) is defective in this prefilled syringe"; PAIN IN EXTREMITY (non-serious) with onset 2023, outcome "recovered", described as "sore arm". Additional information: It was reported that the reporter had a malfunctioning pneumococcal 20-valent conjugate vaccine prefilled syringe. It was stated the healthcare professional tried to vaccinate a patient today (20Apr2023), the needle was placed correctly on the patient's arm but as soon as they tried to press the medication out, all of the liquid leaked from the Luer lock. It seems that the luer lock (slip tip) was defective in this prefilled syringe. They have never had a prefilled syringe malfunction on us before and would like to get this one replaced. Upon follow up on 12May2023, the reporter described the medication error as "Luer lock malfunctioned, the vaccine leaked from the side as it was being administered to the patient." The medication error occurred when the product was administered to / taken by the patient. The factor considered to be responsible for the medication error was the Luer Lock malfunction. The product was prescribed by a healthcare professional and was taken as prescribed. The patient was given a PVZCO after the incident. The patient did not experience any adverse event(s) as a consequence of the error. The reporter additionally commented that the prefilled syringe for PCV20 malfunctioned on 20Apr2023, causing all most of all of the medication to leak on the patient's arm. The patient was given a second PCV20 shot, per providers recommendation and the patient agreed. They spoke to the patient on 03May2023 and she stated that she only had a sore arm, but was completely fine; no further side effects. The vaccination facility was the physician office; the vaccine was not administered at the facility. There were no other vaccines administered on the same date with the Pfizer vaccine considered as suspect.  Follow-up (20Apr2023): This is a spontaneous follow-up report received in response to the mail trail sent regarding the confirmation of below mentioned query.  Updated information included: New reporter information added.  Follow-up (12May2023): This is a spontaneous follow-up report received from the same contactable reporter (Consumer or other non HCP) in response to non-HCP letter sent. Updated information includes: patient details (added height and weight); medical history and concomitant therapy (none); suspect drug (added indication and vaccine facility information; updated vaccination time and anatomical location); reaction data (new events: "sore arm" and "Prefilled syringe for PCV20 malfunctioned, causing all most of all of the medication to leak on the patient's arm"); and clinical course details.  Follow-up attempts are completed. No further information is expected.