Nauseous; threw up a little; she keeps falling down, has had 3 falls; hit her head; she has a huge bump on her face that is very painful; she cannot walk straight or without assistance anymore; Vertigo; Weakness in the muscles; a little arm soreness; Body aches; Chills; Could not sleep; Fever; This is a spontaneous report from a contactable nurse (patient). A 52-year-old female patient received the second dose of BNT162B2 (Pfizer BioNTech COVID-19 Vaccine), Batch/lot number: EK9231, Expiry Date: 31Mar2021, via an unspecified route of administration on 06Jan2021 09:00 at single dose in deltoid right for COVID-19 immunisation. Medical history included heart attack from Jul2019. Concomitant medication included diltiazem from 2019 and ongoing at 120mg tablet taken daily for abnormal heart rhythm she did not know of until had heart attack, acetylsalicylic acid (BABY ASPIRIN) from 2019 and ongoing at 81 mg tablet taken daily for heart attack. The patient previously received the first dose of BNT162B2 via an unspecified route of administration on 17Dec2020 for COVID-19 immunisation; she got the Flu vaccine every year and got shingles vaccine in Mar2020 for immunization. She did totally fine after receiving Flu vaccines and the Shingles vaccine. She had no side effects from the Flu vaccines except maybe a little arm soreness; she had arm soreness for a couple of days after the shingles vaccine; maybe a slight fever and took it easy. This Emergency Room Nurse (patient) received her second dose of Pfizer BioNTech COVID-19 Vaccine on 06Jan2021 around 9:00am. She went back to work, worked around 6-8 more hours that day and was fine. She went home and around 8-10 hours after she got the second dose on the evening of 06Jan2021 she had a little arm soreness and body aches. Last night all night she had chills; she could not sleep; fever. This morning: 07Jan2021 she was so nauseous that she got up and tried to get to the bathroom where she threw up a little. She reported as of 07Jan2021 she kept falling down: She fell in the bathroom this morning first when she was trying to get to the bathroom to throw up; During the second fall she was going on the stairs and fell, and hit her head; she had a huge bump on her face that was very painful now that she thought was from that second fall; and she had the third fall this evening; she cannot walk straight or without assistance anymore, she had been on the couch all day. She has had vertigo all day and weakness in the muscles. Chills was described as unbearable, heavy chills that she could not control. Fever: Temperature of 102-102.4 degrees Fahrenheit. The high fever hit around 3:00am on 07Jan2021. When her high fever hit around 3:00am she thought she would go to the emergency room but she did not want to scare her family so she stayed home and tried to pull through it. Today she took a Tylenol after she threw up this morning just to get through the day. Since she cannot walk without assistance or walk straight today that's the only lingering symptom that really worries her; she may go to the emergency room tonight if she did not get any better. She just did not want to scare her family and the emergency room was another copay cost so she really did not want to go to the emergency room at her workplace; but she may go there tonight and be kept overnight under observation. Prior to taking this second dose of Pfizer BioNTech COVID-19 Vaccine she was completely fine. She expected to have body aches, chills and fever; but she never thought the Pfizer BioNTech COVID-19 Vaccine would put her into a place where she is falling like this with the nausea and vertigo; she has never in her life had vertigo or falling like this. She reported she had no other vaccinations on the same date as Pfizer BioNTech Vaccine second dose. Has had no other vaccines in the recent past. She had never felt like this before with any other vaccines; she had never felt so weak in her muscles and never fallen down like this with any other vaccines. Seriousness criteria and outcome of all events unknown. The reporter considered all events were related to Pfizer BioNTech COVID-19 Vaccine.