eyes are heavy; Fever; sore arm; chills; 4 year old patient an increased dose; vaccine was diluted with .2 mls  (0.2) instead of 2.2 mls; This is a spontaneous report received from contactable reporter(s) (Pharmacist) from medical information team.  A 4-year-old female patient received BNT162b2 (BNT162B2), on 23Aug2022 at 16:32 as dose 2 (maroon cap), single (Batch/Lot number: unknown, Expiration Date: 31Dec2022) at the age of 4 years, in left deltoid for covid-19 immunisation. The patient had no relevant medical history. There were no concomitant medications. Vaccination history included: BNT162b2 (expiry date 30Jan2023, lot FT9142 , administered: left deltoid), administration date: 28Jul2022, when the patient was 4-year-old, for Covid-19 immunization. The following information was reported: OVERDOSE (non-serious) with onset 23Aug2022, outcome "unknown", described as "4 year old patient an increased dose"; PRODUCT PREPARATION ISSUE (non-serious) with onset 23Aug2022, outcome "unknown", described as "vaccine was diluted with .2 mls  (0.2) instead of 2.2 mls"; PYREXIA (non-serious) with onset 24Aug2022, outcome "unknown", described as "Fever"; CHILLS (non-serious) with onset 24Aug2022, outcome "unknown"; ASTHENOPIA (medically significant) with onset 24Aug2022, outcome "unknown", described as "eyes are heavy"; PAIN IN EXTREMITY (non-serious) with onset 24Aug2022, outcome "unknown", described as "sore arm". The patient underwent the following laboratory tests and procedures: Pyrexia: (24Aug2022) 102 Fahrenheit, notes: this morning around 8:00 am and she reported the patient's fever was 102 degrees Fahrenheit. Therapeutic measures were taken as a result of asthenopia, pyrexia, pain in extremity, chills.  Clinical course: Reporter, a pharmacist, asked if there is any post market information in regards to giving a 4 year old patient an increased dose of the Pfizer covid 19 vaccine maroon cap. Reporter asked specifically is there information on increased side effects that occur in patients 4 or below due to vaccine error. Reporter stated the vaccine was diluted with .2 mls (0.2) instead of 2.2 mls. Reporter stated this was the second dose for the child. Reporter asked what is the duration of the side effects, specifically fever and how many. Reporter stated he needed information on revaccination in this situation and transferring agent provided call recording notification and caller states to see if they need the 3rd dose or not, agent states if incorrect dose was administered do not repeat the dose and do not repeat 2nd dose and if still administering 3rd dose; states the patient got the 2nd dose and if it is an administration error result, a higher subsequent dose may be administered in recovery interval dose may be delayed and to assess it on a case by case basis; this information was stated to the reporter by the transferring agent. Reporter verified the information provided by the transferring agent but stated the last part does not sound right and the vaccine was not diluted with 2.2 mL but was diluted with 0.2mL but the administered vaccine dose itself was 2.2mL. For seriousness criteria, he would say with the patient's moderate side effects right now he would say the event is disabling and as of now she does not need to be hospitalized but it would be either medically significant or disabling or both. Patient developed fever that started this morning in the middle of the night, sore arm, chills and one significant side effect is her eyes are heavy and this was reported by her mother; these symptoms are ongoing and he does not know the outcome but they began this morning around 8:00am and she reported the patient's fever was 102 degrees Fahrenheit. For treatment her mother was administering either acetaminophen or Tylenol but not medication treatment so far other than this over the counter treatment. No visit to emergency room or physician office was required. No relevant family medical history. No relevant test. No prior Vaccinations (within 4 weeks). No adverse events following prior vaccination.  Causality: Reporter stated causality as yes because of the increased dose and then clarified it was increased strength as the dose was the same of 0.2mL so it would be due to increased strength.  The information on the batch/lot number for BNT162b2 has been requested and will be submitted if and when received.; Sender's Comments: As per the available information the causality of the event Asthenopia with the suspect BNT162B2 can not be ruled out completely. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Ras, Ethics committees, and Investigators, as appropriate.