The reporting of this event is intended to bring attention to and address my complaint regarding an incident that recently occurred. My hope is that not only will my complaint be heard, but resolutions will be put in place to prevent this incident from occurring again. Currently, my 2 children are under the care of the staff. The incident and complaint is based on the fact that a medical staff erroneously administered the incorrect vaccine for both my children during a nursing appointment. The events from this incident are outlined as follows: After many hours of research, my husband and I made an informed decision for our children to receive a COVID-19 vaccination. This research led us to our decision in choosing the Moderna vaccine instead of the Pfizer vaccine based on a host of reasons, which included the dose requirements for full immunization. My appeal for only the Moderna vaccine was first made known to staff while scheduling the appointment on the nursing line. A nurse spoke with me at length. She confirmed with fellow nurses that they offered Moderna and ensured that it was noted the mother is requesting Moderna vaccine. This note was emphasized and relayed back to me based on her clinical experience that Pfizer was more commonly administered and that Moderna was still relatively new for young children. She ensured that her note in the system would reflect our choice of the Moderna vaccine. I followed that request for the Moderna vaccination for our children by scheduling subsequent appointments on July 26, 2022 and August 23, 2022. The fact that these two appointments were spaced exactly 4 weeks apart for the Moderna dosing requirements gave me the assurance that in addition to the nurse's note, it would be completely understood by the staff that our children were receiving the Moderna vaccination. If my husband and I preferred the Pfizer vaccination, then we would have made three appointments for the dosing requirements versus two. I attended the scheduled July 26, 2022 appointment for my children with the knowledge that I had previously over-communicated the purposes of  this visit as well as the requested Moderna vaccination. My children were seen by a medical assistant (MA) and after she administered the vaccines, I confirmed with her that she had in fact just administered Moderna. She had a look of shock on her face and admitted that she had just administered Pfizer and not Moderna as indicated in the system. After explaining to the MA she just incorrectly administered the wrong vaccine, she briefly left the patient room and upon returning explained she didn't see any note indicating Moderna. She even had someone check behind her and they couldn't see anything either.  I then asked the MA how many shots were now needed for our children to be fully immunized with Pfizer. She stated just 2. Like Moderna. I informed her per the CDC it stated 3 in total were needed for Pfizer. She then became confused and sought clarification again. Upon returning she apologized stating that it is in fact 3 shots needed for Pfizer and not 2 as she originally stated. While checking out at the front desk the receptionist also incorrectly told me only 2 shots were needed for Pfizer and the 3rd was a booster/optional. He then cancelled the August 23, 2022 Moderna vaccine appointment and a Pfizer vaccine appointment for only the second dose was made for August 17, 2022. The receptionist then stated that he will send a message to the nurse manager for her to give me a call to further discuss today's incident and answer questions I may have regarding the Pfizer vaccine. The very next day, July 27, 2022 I called the nurse line back, since I had not received a call from the nurse manager  to verify that a 3rd dose was required and to ensure a 3rd appointment was made. The nurse I spoke to verified she could, in fact, see the initial note indicating our Moderna vaccination request and apologized the wrong vaccination was given.