Client received dose 1 of the COVID19 Pfizer vaccine (Lot# EW0187 Exp 08/31/21) at 13:32 from RN1.  RN1 reported that within 5 seconds of receiving the vaccine, the client reported she felt dizzy and experienced a syncopal episode for 2-3 seconds.  As the syncopal episode was occurring, ancillary staff, requested RN2 radio for a Lead Nurse & EMT.  At 13:34 Lead RN arrived at station 6, radioed for an EMT, and observed client sitting up in the vaccination chair being held by her mother and RN1.  Lead RN noted client?s head was down with her eyes open, exhibiting pallor and was diaphoretic.  Lead RN asked client her name and how she was feeling.  Client did not respond.  Co-Lead RN entered the room at 13:35. RN1, Lead RN, Co-Lead RN, and client?s mother guided client to the floor, laid her in a supine position, lifting her legs and feet on a chair.  Co-Lead RN removed client?s mask, continued to ask client her name.  Within 2-3 seconds of repositioning client, she became responsive and alert & oriented to person, place, time, and event.  Client also immediately stated, ?I?m fine.?  EMT1, EMT2, and EMT3 came to the station at 13:36 with a zero-gravity chair.  The EMTs assisted client into the zero-gravity chair.  Client?s mother stated client has no underlying health conditions, no allergies, and that birth control is the only medication the client takes.  The client confirmed this by nodding her head in agreeance.  EMT2 gave client a bottle of water and the client immediately started drinking the water.  Lead RN asked client if she had eaten or drank anything today.  Client?s mother stated she did not realize her daughter had not eaten or drank anything prior to coming to get vaccinated.  Client stated she was given a granola bar downstairs at check-in and ate it before receiving the vaccine.  At 13:45 EMT1 took vitals.  Both EMT1 & EMT2 were unable to obtain client?s blood pressure (HR:61, O2Sat:  97%).  Lead RN asked client and her mother what the client?s normal blood pressure is.  Client and her mother did not know, and client?s mother indicated that the client is an athlete in good shape.  At 13:48, EMT3 took client?s blood pressure, which was 100/60.  Client?s mother stated client was anxious about being vaccinated and has fainted when anxious in the past, but the last time was around 5 years ago.  Client stated she was feeling better and no longer feeling dizzy.  Client stated she just ?feels hot.?  Lead RN brought client an ice pack to put behind her neck and damp paper towels to wipe her face with.  At 13:59 EMT3 took client?s vitals (BP:  118/70, HR: 65, O2Sat 98%).  Lead RN observed that client?s color was returning to her face and client was less diaphoretic.  Client finished her bottled water and was given another by EMT2, which she started drinking.  Lead RN asked client if she felt she could stand up.  Client stood up and stated she was ?feeling fine.?  At 14:05 all 3 EMTs escorted client and her mother to the observation room where she was monitored for an additional 30 minutes.  At 14:30 Lead RN went to the observation room where EMT1was taking client?s vitals (BP:  110/70, HR: 60, SPO2 Sat 98%).  Lead RN observed that client?s color had fully returned, and client was no longer diaphoretic.  Client stated she ?felt fine? and was hungry.  Client?s mother stated she would take client to get something to eat and EMT2 gave client an additional snack that client took with her when she left.  Client and her mother left at 14:30. Client was walking with a steady gait when she exited the building.