On 5.13.21, the closing pharmacist,  and the closing technician, filed a salvage claim of 2mls of unused Moderna Covid Vaccine (4 immunizations) that had not been used during the day. The product was salvaged under the Senior technician, as he had visually instructed both of them how to correctly salvage unused vaccine before he left his shift at 6:30 pm. Once salvaged, neither employee correctly placed the vial in the hazardous waste bin and left in on the counter in the vaccine area of the pharmacy.  On the morning of 5.14.21, the opening pharmacist, and opening technicians, saw the unused vaccine vial from the previous evening 5.13.21, and did not correctly dispose of the vial nor quarantine the vial. They explained they did not know where to dispose of it and was waiting on senior tech to arrive for his shift for further direction.  At 10am, when the first patient arrived for a vaccine, tech checked in the patient and gave patient the VAR. While patient was filling out VAR, tech removed one Moderna vial from the refrigerator so the vaccine could come to room temperature for the appropriate amount of time. She popped the plastic vial lid off of the vial and cleaned the rubber stopper with alcohol. Once the patient was through filling out the VAR, technician  took over the transaction and headed to the vaccine area. Technician saw that 2 vials were present, unknowing that one vial was expired and quaratined, and added a tik mark to the Moderna Beyond Use Time label thinking 6 shots had already been given earlier in the day and drew up the syringe on current and 2 additional patients from the expired vial. This is verified by the tik marks added to the Beyond Use Label by tech in a different colored ink pen. At a point after these three said immunizations were given, senior tech saw that there was 2 vials on the counter realizing that one vial was from the day before and correctly disposed of the vial.  Later in the day, senior tech told everyone to remember to put tick marks on the vials they use and tech said she had placed her tiks on the 1st vial Beyond Use Label. Senior tech said there was no vial from earlier and asked if she has used the expired vial before he got there. Tech said she drew up at least 3 shots from the unknowingly expired vial.  Upon learning this information, senior tech looked for the on duty pharmacist,  as she heard the same information that was just presented. Pharmacist asked senior tech to go ahead and reach out to the pharmacy manager,  to make sure we correctly document this in system. Pharmacist then reached out to store manager,  to go over the correct standard operation procedures of this said event.  Pharmacist first contacted store Liability Intake Process to report the immunization event. The responding agent took the information that they needed and gave us reference report number. The pharmacy is to call back once we know the names and date of births of the corresponding patients who were involved. Next, pharmacist called the Moderna manufacture to report the event and to ask for information on potential side effects for the patients involved. Again, the responding agents gathered all the information they needed and escalated the information to their Medical Affairs team who will reach back out to us shortly. They advised pharmacist that this event is to be reported to the  reporting system.  The pharmacy vaccine area is in a blind spot for security cameras but by deductive reasoning it was determined by pharmacy team the 3 patients who received the expired vaccine. After the correct patients were identified, pharmacist reached out to the patients and was unable to speak to any of them but left voicemails asking them to call back 5.15.21 after 9 am and speak directly to the pharmacist due to an urgent matter.  Lastly, pharmacist then submitted the according reports to both the adverse reporting systems.