Entire undiluted vial drawn up (0.3ml) and administered to patient; Entire undiluted vial drawn up (0.3ml) and administered to patient; having a sore arm after the overdose; This is a spontaneous report received from a contactable reporter(s) (Other HCP) from medical information team.  A 12 year-old female patient received bnt162b2 (BNT162B2), administration date 24Sep2021 (Batch/Lot number: unknown) as dose 1, 0.3 ml single for covid-19 immunization. The patient's relevant medical history and concomitant medications were not reported. The following information was reported: PRODUCT PREPARATION ERROR (non-serious), OVERDOSE (non-serious) all with onset 24Sep2021, outcome "unknown" and all described as "Entire undiluted vial drawn up (0.3ml) and administered to patient"; PAIN IN EXTREMITY (non-serious) with onset 2021, outcome "recovered" (2021), described as "having a sore arm after the overdose". Additional information: Question: Inbound caller is a Registered Nurse that works at (hospital name). She is reporting the following administration error on a 12 year old female patient. Caller noted that of of now no VAERS report has been filed and she found out about this today. Nurse did not have access to lot# at this time.Patient received first dose of Pfizer Covid 19 vaccine on 24Sep2021. Entire undiluted vial drawn up (0.3ml) and administered to patient. Nurse confirms vial had not been reconstituted. As of to date, patient experienced no side effects. Seeking guidance on next steps and revaccination. Would like document to be e-mailed to review with colleagues. E-transmitting AE details. Caller declined warm transfer at this time as she has a Risk Management meeting to attend. Response: Provided disclaimers and Spoke on attached document. "Please note that Pfizer is independent of these recommendations. Pfizer is unable to make any specific treatment recommendations for individual patients; clinical judgement based on the medical history and the clinical status of a specific patient should dictate the appropriate actions to be taken. (Pfizer-BioNTech COVID-19 Vaccine only) No diluent, resulting in higher than authorized dose (i.e., 0.3 ml of undiluted vaccine administered) Do not repeat dose. Inform the recipient of the potential for local and systemic adverse events. Noted: If the administration error resulted in a higher-than-authorized vaccine dose, in general the second dose may still be administered at the recommended interval. However, if local or systemic side effects following vaccination are clinically concerning (outside of the expected side effect profile), lead to serious adverse reactions, or are ongoing at the time of the second dose, the decision to administer the second dose may be assessed on a case-by-case basis." Referred to CDC for revaccination guidance. E-mailed attached document as requested. Offered end of call survey. Phone out 3:17 pm. Phone answered by reporter who provided some additional details: Comments/Narrative: Please clarify the type of medication error.- overdose Please provide the stage of medication error (e.g., prescribing, dispensing, preparation, and administration). Preparation and administration Please provide contributing factors to the medication error. - Pharmacist had not read the package instruction or company instruction from internal e-mail on how to dilute the vaccine and draw it up. Please clarify if the medication error affected the patient or consumer with clinical consequences. Phone out 3:17 pm. Phone answered by reporter who provided some additional details. Confirmed the dose administered was 0.3mL of undiluted vaccine and not 0.45ml for the full vial. However, she mentioned there was only 0.3mL in the vial at the time, so that's why she initially thought it was a full vial overdose. The patient reported having a sore arm after the overdose, but has since recovered. No further information was provided.  Follow up (06Oct2021): This Nurse (reporter) reported in response to HCP letter sent via telephonic follow-up activity outbound call which included that: information added in narrative.  Follow-up attempts are completed; information about lot/batch number cannot be obtained. No further information is expected.