seizures; rapid heart beats; losing your menstrual cycle for months/lost cycle 5 months; Lost a lot of weight; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 19-year-old female patient received BNT162b2 (BNT162B2), on 11Jan2022 as dose 3 (booster), single (Lot number: FJ5683) at the age of 18 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "high blood pressure" (unspecified if ongoing), notes: Had high blood pressure, was high every time she went to doctor. The patient's concomitant medications were not reported. Vaccination history included: BNT162b2 (dose 1, single, LOT: EW0151, NDC EXP: Unknown, Anatomical location : Left arm), administration date: 20Apr2021, when the patient was 18-year-old, for Covid-19 immunization; BNT162b2 (dose 2, single, LOT: EW0173, NDC EXP: Unknown, Anatomical location :Left arm), administration date: 11May2021, when the patient was 18-year-old, for Covid-19 immunization; flu (had flu shot 14Oct2021, nurse said do not get flu shot), administration date: 14Oct2021, when the patient was 18-year-old, for covid-19 immunization. The following information was reported: HEART RATE INCREASED (hospitalization, medically significant) with onset Jan2022, outcome "unknown", described as "rapid heart beats"; MENSTRUAL DISORDER (non-serious) with onset May2022, outcome "unknown", described as "losing your menstrual cycle for months/lost cycle 5 months"; SEIZURE (hospitalization, medically significant) with onset May2022, outcome "not recovered", described as "seizures"; WEIGHT DECREASED (non-serious) with onset 2022, outcome "unknown", described as "Lost a lot of weight". The patient was hospitalized for heart rate increased, seizure (start date: 15Aug2022, discharge date: 16Aug2022, hospitalization duration: 2 day(s)). The events "rapid heart beats", "seizures", "losing your menstrual cycle for months/lost cycle 5 months" and "lost a lot of weight" required physician office visit and emergency room visit. The patient underwent the following laboratory tests and procedures: Electrocardiogram: (Jan2022) rapid heart beat, told her it was probably just i, notes: side effect; Electroencephalogram: (15Aug2022) Unknown Results, notes: they could not find anything conclusive to say it was or wasn't seizures. She was admitted to hospital overnight for EEG on 15Aug2022; Heart rate: (May2022) rapid heart beats; Weight: (unspecified date) 106, notes: Weight: Was 108, is now 106 right now. She was 120 something; (unspecified date) 120, notes: Weight: Was 108, is now 106 right now. She was 120 something; (unspecified date) 108, notes: Weight: Was 108, is now 106 right now. She was 120 something; (May2022) 117, notes: Thinks maybe she was 117 in May2022. Therapeutic measures were taken as a result of menstrual disorder.  Clinical course: Indication for Use of vaccine in Case was reported as didn't want to catch Covid. No other conditions. Patient did not get any vaccinations within 6 weeks of Covid booster shot. No Family Medical History Relevant to Adverse Events. Patient had 2 Pfizer shots and the Pfizer booster; With the first 2 shots, didn't have any problems. Then they came out and said to take the booster 3 months after the first ones. After that, is not taking anymore. Took booster to go back to school, was college student and had to take it. Concomitant Products/Medical Conditions included had high blood pressure, was high every time she went to doctor. They would say it was white coat syndrome (patient did not think it was that). Thinks it was high before she got Covid. Does not know if something triggered her blood pressure but she always had high blood pressure. Was finally diagnosed from the cardiologist. Thinks she had high blood pressure before the booster but was not diagnosed with high blood pressure until after that. Had been dealing with that since eight grade. Thinks the booster, is what messed her up. Before that, she was fine. Thinks she had Covid before getting the shots, before they knew what Covid was. Shortly after booster, began to have rapid heart beats which was known as a side effect. Patient went to emergency room 14Jan2022, 3 days after booster. Went to emergency room with rapid heart beat. They checked her, did EKG, told her it was probably just side effect. Clarified that she was admitted to hospital overnight for EEG on 15Aug2022. When she kept having episodes on the EEG, they could not find anything conclusive to say it was or wasn't seizures. When having episodes, they took her to emergency room and they had her stay one night to for the EEG. Will have the ambulatory EEG 10Jan2023. The neurologist wants to see if they can capture anything with the episodes she is having and see if they look like seizures. Patient was having seizure like episodes, almost like freezing and they are not like tonic-clonic or those seizures that where they shake but these were seizure like episodes. Lost a lot of weight after the Pfizer shot. Are these side effects that a lot of people are reporting. The seizures, she thinks she has seen that but losing her cycle. Patient would like to know if seizures and losing menstrual cycle for months are symptoms other people have reported after having the booster. There's a lot of articles where they mention that the women cycles disappear. Is in the process of changing to different doctor but current doctor will have all of her records. Kept reporting this to the doctors but they kept dismissing it, when her cycle stopped. Started searching it and seeing that other people were experiencing it. Talked to the doctor today and they told her to maybe report it to Pfizer. Nobody had that before. Seizures, Also started May2022. Is still experiencing them now. Is scheduled for 72 hour ambulatory EEG, 10Jan2023. Is going to neurologist and they want to make sure there is nothing going on with the brain. Has not experienced anything like this until she took the Pfizer booster. Outcome of event was it has gotten worse. Is now starting to urinate on herself and has to wear pads. Clarified that this only occurs when she is having seizures. Is going back to see the neurologist. Weight loss, first noticed, she thinks, maybe in May or Jun2022. Thinks maybe she was 117 in May2022 then, all of a sudden, started dropping, almost monthly. Before that, had healthy appetite, couldn't eat right after booster. With all her heart problems she experienced from the booster, her primary care physician sent her to the cardiologist. Nothing was wrong with her heart and they were doing all this stuff for her heart. Lost cycle 5 months, Didn't have any cycles from May2022 until Nov2022. Saw a specialist and they put her on this medicine that made her cycle come back. Only took it 3 days and it was making heart hurt and chest hurt. Took that and cycle came back on, so it did work. Clarified that the medicine previously mentioned that she cause the chest pain was like a low dose birth control pill, to get her cycle to come back. The gynecologist gave her that name of that medication provided as Norethindrone. It made her chest hurt. Went back to gynecologist and they told her not to take it. Her cycle came on 3 days later. Lost her cycle for 5 months. It finally came back but now.