IGG Spike, over 150; he was so scared; had suicidal thoughts; was ill-tempered; forgot things; his personality was so different; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 75 year-old male patient received bnt162b2 (BNT162B2), administration date 01Oct2021 (Lot number: 30145BA) at the age of 75 years as dose 3 (booster), single for covid-19 immunisation. The patient's relevant medical history was not reported. There were no concomitant medications. Vaccination history included: Bnt162b2 (DOSE 1, SINGLE, LOT- EK4176), administration date: 13Jan2021, when the patient was 74 years old, for COVID-19 immunization; Bnt162b2 (DOSE 2, SINGLE, LOT- EL9261), administration date: 01Feb2021, when the patient was 74 years old, for COVID-19 immunization. The following information was reported: SUICIDAL IDEATION (medically significant, life threatening) with onset Oct2021, outcome "recovering", described as "had suicidal thoughts"; ANGER (non-serious) with onset Oct2021, outcome "recovering", described as "was ill-tempered"; MEMORY IMPAIRMENT (non-serious) with onset Oct2021, outcome "recovering", described as "forgot things"; PERSONALITY CHANGE (non-serious) with onset Oct2021, outcome "recovering", described as "his personality was so different"; BLOOD IMMUNOGLOBULIN G INCREASED (non-serious), outcome "unknown", described as "IGG Spike, over 150"; NOSOPHOBIA (non-serious) with onset Oct2021, outcome "recovering", described as "he was so scared". The patient underwent the following laboratory tests and procedures: blood test: blood immunoglobulin g increased, notes: Blood immunoglobulin G increased; sars-cov-2 antibody test: 150, notes: Mentioned that his IgG spiked and was about 150 and the usual value was supposed to be below 1 but his was about 150.  Clinical Course: Clinical Course: He mentioned that for the first two, he had no pain or anything and at the start of the booster there was nothing as well, but by middle Oct, he had some horrible, really bad side effects. He mentioned that he "started to go sideways", was ill-tempered, forgot things, his personality was so different, and had suicidal thoughts. He mentioned that that it was really bad for him and he was so scared that he wanted to end things then and there. This lasted from Oct, Nov, and Dec. By Jan, things started to go back little by little and he could notice a change but the side effects are still there. He mentioned that his doctored ordered some blood tests for him and one of the test included a test for COVID called "SARS COVID SEMI 2N" which revealed that his "IGG Spike" was above 150 whereas the normal value should be below than 1. He is asking why is this and what could happen to him. on 01Oct2021 he got his booster dose and mentioned that during the injection there was no pain or nothing, but 2 weeks after the booster he started having really bad side effects, states it was horrible, still has some of them but it has started to subside in Jan2022 this year. In the middle of Oct2021 he started to go sideways, personality was different, he was ill tempered and forgot things, had some suicidal thoughts, he was scared, started cutting off people in his life, happened in Oct, Nov, and Dec of 2021. The doctor did some blood tests on him to investigate the side effects, unable to confirm the blood tests, one was SARS Covid semi 2N, agent states he was kind of in a panic during the call. Mentioned that his IgG spiked and was about 150 and the usual value was supposed to be below 1 but his was about 150. Caller confirms the details experienced as provided by the transferring agent. States his symptoms have improved however he is still scaring himself sometimes.