rare appendicitis; Rectal bleeding; he become "deathly sick"; Diarrhea; severe headache; had a fever 103; was throwing up; Constipation; behavior was bizarre; pain in his stomach; stiff neck; could not hold food down; lost 16 pounds; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the parent.  A 18 year-old male patient received bnt162b2 (BNT162B2), administration date 22Dec2021 (Batch/Lot number: unknown) at the age of 18 years as dose 2, single for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose: 1), administration date: 22Nov2021, when the patient was 18 years old, for COVID-19 Immunization.  The following information was reported: APPENDICITIS (hospitalization, medically significant) with onset 01Jan2022, outcome "unknown", described as "rare appendicitis"; RECTAL HAEMORRHAGE (medically significant) with onset 11Jan2022, outcome "unknown", described as "Rectal bleeding"; ILLNESS (medically significant) with onset 01Jan2022, outcome "unknown", described as "he become "deathly sick""; VOMITING (medically significant) with onset Jan2022, outcome "unknown", described as "was throwing up"; PYREXIA (medically significant) with onset Jan2022, outcome "unknown", described as "had a fever 103"; CONSTIPATION (medically significant) with onset Jan2022, outcome "unknown", described as "Constipation"; DIARRHOEA (medically significant) with onset Jan2022, outcome "unknown", described as "Diarrhea"; ABNORMAL BEHAVIOUR (medically significant) with onset Jan2022, outcome "unknown", described as "behavior was bizarre"; ABDOMINAL PAIN UPPER (medically significant) with onset Jan2022, outcome "unknown", described as "pain in his stomach"; HEADACHE (medically significant) with onset Jan2022, outcome "unknown", described as "severe headache"; MUSCULOSKELETAL STIFFNESS (medically significant) with onset Jan2022, outcome "unknown", described as "stiff neck"; DYSPHAGIA (medically significant) with onset Jan2022, outcome "unknown", described as "could not hold food down"; WEIGHT DECREASED (medically significant) with onset Jan2022, outcome "unknown", described as "lost 16 pounds". The patient was hospitalized for appendicitis (start date: 11Jan2022, discharge date: 16Jan2022, hospitalization duration: 5 day(s)). The events "rare appendicitis", "rectal bleeding", "he become "deathly sick"", "was throwing up", "had a fever 103", "constipation", "diarrhea", "behavior was bizarre", "pain in his stomach", "severe headache", "stiff neck", "could not hold food down" and "lost 16 pounds" were evaluated at the emergency room visit. The patient underwent the following laboratory tests and procedures: body temperature: 103; colonoscopy: no blockage from the bleeding; computerised tomogram: unknown results; unknown results; unknown results; scan: unknown. Therapeutic measures were taken as a result of appendicitis, rectal haemorrhage, illness, vomiting, pyrexia, constipation, diarrhoea, abnormal behaviour, abdominal pain upper, headache, musculoskeletal stiffness, dysphagia, weight decreased. Clinical information: Caller states her son withheld got the Pfizer vaccine, 1st dose on 22Nov2021 and 2nd dose on 22Dec2021. States that on 1Jan2022 she thought he was going to die. States she took him to urgent care 3 days later and thought he had Covid as his friends had Covid symptoms that were nothing. States his symptoms were really strange and didn't know if he had Covid and they turned him down and wouldn't let anyone in the office and she couldn't get in touch with his doctor. States that about 4 days later he ended up in the ER and was admitted on 11Jan2022 and discharged on 16Jan2022 and it was the most disgusting this ever. Caller states she was a former Pfizer employee in research and doesn't want to talk bad about Pfizer, her son was on a Pfizer drug in the hospital and it saved his life. Caller states only a couple days after that he got signs and symptoms and was diagnosed with appendicitis but the rarest thing they had ever seen. Caller states it did not hit her, she was very distraught, he is only 18 years old and she didn't connect that the 2 could it possibly be from the vaccine. Caller states she spaced hers out 3 months later from the 1st as she felt that was right. No further details provided. Caller states he was an identical twin and she was waiting for the other to get symptoms and he didn't and they have the same DNA and she doesn't know why it happened to her son. Caller states she doesn't know what's going to happen, she was not going to use. States she gets a monthly pension and worked here for 14 years and left when she had kids. Caller states the bottom line is she would be ok if the doctor would have said this is an acute appendicitis and that was all but they said it was the most unusual thing they had ever seen. Caller states his last dose is today and he is taking these 2 drugs, that once you get released he had to go on medication. States he had IV's in both arms. Caller states that call handler can't reveal what other people have said, she was a secretary in research and she saw everything weird. Caller is asking that within the time frame for him to become deathly sick on 1Jan2022. States that on 22Dec2021 got the 2nd dose and got sick on 1Jan2022, was that a significant amount of days as she has heard it takes 2 weeks for the 2nd dose to get in the body. Caller declines to make a report stating she needs to get food and would like to talk to medical information. Caller states she didn't know the severity of this. States he was throwing up, had a fever 103 and it went down and up and he had constipation and diarrhea. States on 11Jan2022 when he started bleeding from behind, rectal bleeding, thank God she has a pleather couch and not leather. States he said ma there is something pouring out of me and there was blood everywhere and they saved his life because she believes he had a form of meningitis. Caller states his behavior was bizarre, he would run into the shower 3-4 times a day and said he was trying to relieve the pain in his stomach and he had a severe headache. Caller states he would try to take Tylenol and went to urgent care 4 days later on 4Jan2022 or 5Jan2022 and they were not letting anyone in as they were using it as a Covid site for testing. Caller states at the hospital he did not have Covid. States he was beyond bizarre. Caller states he had a stiff neck which she knows is part of meningitis. Caller states he had severe diarrhea and could not hold food down. States he lost 16 pounds, he is 6 feet and lost 16 pounds and is a body builder and you couldn't make out his features. States they want him to get the booster and he is not getting it and she was not having him die. States her husband died in the line of duty and she has been taking care of the kids since they were age 7 and she can't afford 6 days and the bills are astronomical but of course they are not going to end and will keep coming. States he had a colonoscopy that showed no blockage from the bleeding and 3 CT's and a body scan. In the article it stated there were 285 cases already of appendicitis, she has it in internet search and send it to her email.   The lot number for bnt162b2 was not provided and will be requested during follow up.