Second dose: platelets dropped; This is a spontaneous report from a contactable male consumer (patient). A male patient of an unspecified age received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: Solution for injection, Batch/Lot Number: unknown) via an unspecified route of administration on 10Mar2021 at 11:25 as dose 2, single for covid-19 immunisation. Medical history included idiopathic thrombocytopenia from Apr2018 to an unknown date was diagnosed in Apr2018. He was diagnosed in Apr2018. He had gone for some routine blood work for a routine colonoscopy and the doctor's office called him and told him to go to he emergency department because his platelets were 17,000. He was in the hospital until 23Apr2018.The hospital reran the platelet test and it was 19,000. He had no bleeding and no bruising, he was fine and ultimately discharged. After his diagnosis in Apr2018 of idiopathic thrombocytopenia he was getting his blood drawn often like twice a week, then once a week, then once every 2 weeks and now he gets his blood drawn in the first week of every month. The patient's concomitant medications were not reported. Historical vaccine included bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: Solution for injection, Batch/Lot Number: unknown) via an unspecified route of administration on 17Feb2021 at 11:20 as dose 1, single for covid-19 immunisation and experienced saw blinking lights, felt imbalanced and blood pressure dropped. The patient experienced his platelets dropped after the second Covid 19 vaccine. With the second Covid 19 vaccine he checked his blood pressure before he got the Covid 19 vaccine and it was 140 mmHg systolic. He was perfectly alright. He only notices his blood pressure low when it's below 110mmHg systolic. He did exercise and his blood pressure was usually 117mmHg systolic. He got the second Covid 19 vaccine on 10Mar2021 and he got his blood drawn again. Prior to the second vaccine his platelets recovered, no problem to 180,000 but after the vaccine dropped to 104,000 or so. He had the exact platelet numbers in his paperwork. Patient got blood drawn on 15March2021, he had the lab work on 05Mar2021, 02Apr2021 and 07May2021. It could be 10Mar2021 and 20Mar2021 patient used antibiotic, Doxycycline and from 20Mar2021 to 30Mar2021 antibodies 500 milligrams times to a day approximately. He repeated the blood drawn that, platelets on 11Mar2021 was 180 thousand however he got a real above 40% drop in his platelets value. The second time the blood pressure patient was fine. He had the lab work before 10Mar2021 on 15Mar2021 and then He had 22Mar2021 and he had a lab work from first week of this April and the first week of May, those ones are all the lab work I had. The patient underwent lab tests and procedures which included blood pressure measurement: 95 mmhg, 126 mmhg 125 mmhg, 115 mmhg, 107 mmhg, 140 mmhg, 110 mmhg,117 mmhg , 95 mmhg on unspecified date, 127/72 mmhg on Feb2021, blood pressure measurement: 107/66 mmhg on 22Feb2021, blood test: unknown results on 05Feb2021, blood test: unknown results on 05Mar2021, blood test: unknown results on 02Apr2021, blood test: unknown results on 07May2021 and 15Mar2021. Plate late count 17,000, 19,000, 174,000, 110,000, 75,000, 104,000, 180,000 on unspecified date, on 08Jan2021 was 160000, 104,000 on Feb2021, 107,000 on 22Feb2021, 180,000 on 11Mar2021. The outcome of event was unknown.  Information related to batch/Lot no. was requested.