she inadvertently administered 0.3mL of undiluted Pfizer-BioNTech Covid-19 Vaccine (orange cap) to an 81 year old male and an 81 year old female patient; she inadvertently administered 0.3mL of undiluted Pfizer-BioNTech Covid-19 Vaccine (orange cap) to an 81 year old male and an 81 year old female patient; she inadvertently administered 0.3mL of undiluted Pfizer-BioNTech Covid-19 Vaccine (orange cap) to an 81 year old male and an 81 year old female patient; sore deltoid muscle for a couple days; This is a spontaneous report received from a contactable reporter(s) (Nurse) from medical information team.  An 81-year-old male patient received BNT162b2 (BNT162B2), on 20Jul2022 as dose 4 (orange cap; booster), 0.3 ml single (Lot number: FL8094, Expiration Date: 31Aug2022) at the age of 81 years, in left deltoid for covid-19 immunisation. The patient had no relevant medical history. There were no concomitant medications. Vaccination history included: Bnt162b2 (DOSE 1, SINGLE), for Covid-19 immunization; Bnt162b2 (DOSE 2, SINGLE), for Covid-19 immunization; Bnt162b2 (DOSE 3, (BOOSTER) SINGLE), for Covid-19 immunization. The following information was reported: MYALGIA (non-serious) with onset 2022, outcome "unknown", described as "sore deltoid muscle for a couple days"; PRODUCT PREPARATION ERROR (non-serious), UNDERDOSE (non-serious), PRODUCT ADMINISTERED TO PATIENT OF INAPPROPRIATE AGE (non-serious) all with onset 20Jul2022, outcome "unknown" and all described as "she inadvertently administered 0.3mL of undiluted Pfizer-BioNTech Covid-19 Vaccine (orange cap) to an 81 year old male and an 81 year old female patient". Therapeutic measures were not taken as a result of product preparation error, underdose, product administered to patient of inappropriate age.  Additional information: It was reported that, incorrect formulation of the Pfizer COVID 19 Vaccine that was administered to two 81-year-old patients, one male and one female. The two patients were administered an undiluted 0.3mL dose of the Pediatric Formulation of the COVID 19 Vaccine. It was stated that this results in the patients having received 30mcg, so it actually added up to the appropriate amount of the vaccine for the patients. Given undiluted dose of the pediatric formulation of the vaccine on the day of reporting. When prompted for specific seriousness criteria it was stated as no. Both of the patients waited for a half of an hour after vaccine administration for monitoring. The patient did not received any other medication. The patient had no lab tests. wrong vial was choosen from the vaccine refrigerator. Both patients that received the vaccine had a sore deltoid muscle for a couple days no other reaction conveyed.  Follow-Up (15Aug2022): Follow-up attempts are completed. No further information is expected.  Follow-up (29Aug2022): This is a follow up spontaneous report from a contactable Nurse. This Nurse reported in response to HCP letter sent which included that:  Updated information included: Reporter information, suspect product information (vaccination facility phone number, anatomical location), reaction information (event added) and additional information.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202200992412 Same reporter/ drug/ event for different patient;