covid_test_name_post_vaccination=PCR covid_test_result=Positive; Condition worsen; pericardial effusion; develop GI; Heavier Insomia; dierrea; vomiting; fever; Headache; Hypotensive; Dehydrated; Developed into MISC; Patient said he had 4 vaccines; PCR resulted as positive on 17Jun2021 Nasal Swab; This is a spontaneous report received from a contactable other-HCP (father) reported for old son (patient). A 15-year-old male patient received second dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Solution for injection, Batch/Lot Number: EW0173 F) via an unspecified route of administration in left arm on 07Jun2021 as dose 2, single for COVID-19 immunization. Medical history included ongoing known allergy in mosquito bite (sketter syndrome) an allergic reaction to mosquito bites, as his son has grown up it has become less and less relevant. Concomitant medications were not reported. Patient previously received first dose of bnt162b2 (Dose:01 Lot number: EW0171 Anatomical Location: Arm left) on 17May2021 for COVID-19 immunization. It was unknown if the patient received any other vaccines within 4 weeks prior to the COVID vaccine. Prior to vaccination, was the patient was not diagnosed with COVID-19. Since the vaccination, the patient been tested for COVID-19. History of all previous immunization with the Pfizer vaccine considered as suspect (or patient age at first and subsequent immunizations dates of birth or immunizations are not available. It was reported that my son traveled on 16May2021. Covid test prior traveling negative. On Jun2021, 4 days after vaccination develop GI, heavier insomia, dierrea, vomiting, fever, hypotensive, dehydraeted. On 11Jun2021 experienced pericardial effusion. On an unknown date Jun2021, developed into MISC and was intubated. The patient was hospitalized from 14 Jun 2021 to 6 Jul 2021. Treatment was received. On 15Jun2021, admission at (withheld), (Hidratation IV and IVIGs). On 16Jun2021 condition worsen and Intubated in (withheld). On 17Jun2021, transfer to (withheld) (7 days at PICU, another 7 at pediatrics). On Jun2021, developed a strong insomnia and headache. Events resulted in emergency room/department or urgent care. Treatment received for the adverse event was MISC protocol IVIGsAnakinra, esteroids and others. On an unknown date, Patient said he had 4 vaccines. His son spent 7 days in the ICU and 7 days in the pediatric unit was discharged from the hospital yesterday. Reported that other researchers studying MIS-C in children have seen how the epithelium cells in the intestine become loose, then the protein goes through the blood stream and can start a cytokine storm and asked if we have studies regarding how much S protein is being produced by different age groups; can it be checked how much S protein is going into the bloodstream to see adverse effects of the vaccine and stated he needs more data to see if his son was possibly infected with Covid during his vaccination period or what he previously infected and absolutely asymptomatic. Most MIS-C occurs 4-6 weeks after having Covid. States that for his son to travel he had to have antigen testing, which was negative. His son did well until 3-4 days after the second shot. States at that time his son became ill with vomiting, diarrhea, headache, and insomnia. She took her son to the hospital and they found him to be hypotensive and dehydrated. They started intravenous fluids and their protocols; the hospital did not have all the required medications for their son and recommended he be transferred to (withheld) Hospital. He was very tired and they decided to put him on ventilation for the ambulance drive. States that when they arrived in (withheld), his son was placed in ICU where he was on the ventilator for 5 days, the recuperating for 2 more days. His son was then moved throughout the hospital system until his discharge yesterday. His son's insomnia may have started before he left for the (withheld). States that it was worsened after the vaccine, his son mentioned after his hospitalization that he was actually given 4 shots the day he got his vaccines, assumed it to be some kind of delirium from his son being in the ICU for so long, stated he told his son that was not possible that he got 4 vaccines at once because of the paperwork you have to fill out to get the vaccine, the lady at the vaccination site told him to sit down and then gave shothim four shots. The patient underwent lab tests and procedures which included IgG and IgM resulted as positive on 15Jun2021, PCR resulted as negative on 15Jun2021 Nasal Swab, PCR resulted as positive on 17Jun2021 Nasal Swab. The clinical outcome of the event developed MIS-C and was intubated, vomiting, dierrea, headache, insomnia, hypotensive, dehydrated on an unknown date 2021 was resolved and the event pericardial effusion, develop GI, fever was resolving, the event condition worsen, Vaccination failure, patient said he had 4 vaccines and PCR resulted as positive on 17Jun2021 Nasal Swab was unknown; Sender's Comments: Based on the limited information currently available, the causal association between the event Insomnia, Diarrhea, vomiting, fever, Drug ineffective, COVID-19, Headache, overdose and the suspect drug cannot be excluded. Also, there is limited information in the case provided, the causal association between the event Multisystem inflammatory syndrome in children, Pericardial effusion, Gastrointestinal inflammation, Condition worsened, Hypotensive, Dehydration and the suspect drug cannot be excluded.  The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to RAs, Ethics Committees, and investigators, as appropriate.