Lethargic; brain fog; can't think; exhausted; decreased appetite; muscle pain; Chills; not feeling good; whole body in pain; headaches; sleeping 12 to 15 hours a day; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the parent.  A 30 year-old male patient received bnt162b2 (BNT162B2), administered in arm (Batch/Lot number: unknown) at the age of 30 years as dose 3 (booster), single for covid-19 immunisation. The patient had no relevant medical history. There were no concomitant medications. Vaccination history included: Bnt162b2 (First dose), for COVID-19 immunization; Bnt162b2 (Second dose), for COVID-19 immunization.The following information was reported: LETHARGY (non-serious) with onset 18Feb2022, outcome "not recovered", described as "Lethargic"; FEELING ABNORMAL (non-serious) with onset 18Feb2022, outcome "not recovered", described as "brain fog"; COGNITIVE DISORDER (non-serious) with onset 18Feb2022, outcome "not recovered", described as "can't think"; FATIGUE (non-serious) with onset 18Feb2022, outcome "not recovered", described as "exhausted"; DECREASED APPETITE (non-serious) with onset 18Feb2022, outcome "not recovered", described as "decreased appetite"; MYALGIA (non-serious) with onset 18Feb2022, outcome "not recovered", described as "muscle pain"; CHILLS (non-serious) with onset 18Feb2022, outcome "not recovered", described as "Chills"; MALAISE (non-serious) with onset 18Feb2022, outcome "not recovered", described as "not feeling good"; PAIN (non-serious) with onset 18Feb2022, outcome "not recovered", described as "whole body in pain"; HEADACHE (non-serious) with onset 18Feb2022, outcome "not recovered", described as "headaches"; HYPERSOMNIA (non-serious) with onset 18Feb2022, outcome "not recovered", described as "sleeping 12 to 15 hours a day". Relevant laboratory tests and procedures are available in the appropriate section.  Additional information: She stated her son, got his third shot and ever since then, he has been lethargic, sleeping 12 to 15 hours a day, not eating, his whole body in pain and cannot work. He saw a lot of kids and she does not know what to do for him. It has been a month and the doctors wont see him and she does not think the doctors can do anything. She stated her son could not function and was asking what to do. Caller stated she used to work for Pfizer and was a sales representative clarified she was no longer working for Pfizer and has retired. She stated he stated that he had brain fog, cannot think, was exhausted, sleeping 12 to 15 hours a day, headaches, decreased appetite, muscle pain, chills. Caller stated this all started when her son got his third shot. She stated he texted her on 13Mar2022 and had said it had been going on for 23 days at that time. Caller stated her son was still experiencing all these symptoms and states that was why she was calling. She states it may all still be the same but, she does not really know. He was still missing work and was still not feeling good. Treatment: Caller stated she knows he went to urgent care, and they did a lot of blood work and tests. Clarified that her son did not go to the hospital or ER, he just went to urgent care. Caller stated they ran a whole bunch of tests and were checking for Mono. Her son had been in (urgent care) in Nov2021 and they were checking for parasites. They did not find anything. History of all previous immunization with the Pfizer vaccine considered as suspect was unknown. No additional vaccines administered on same date of the Pfizer Suspect. Adverse event did not require any emergency room or physician office. No prior vaccinations (within 4 weeks). None adverse event following prior vaccinations. None medical History (including any illness at time of vaccination). No family Medical History Relevant to AE(s): No. Relevant Tests was unknown.  The lot number for bnt162b2 was not provided and will be requested during follow up.