DISSEMINATED INTRAVASCULAR COAGULATION; VACCINE-INDUCED THROMBOTIC THROMBOCYTOPENIA; THROMBOCYTOPENIA; DEEP VEIN THROMBOSIS; BILATERAL PULMONARY EMBOLISM; HEART WAS ENLARGED; CYST OF SOME SORT; BALANCE WAS STILL A BIT OFF; DECREASED APPETITE; MALAISE; This spontaneous report received from a consumer concerned a male of unspecified age, race and ethnicity. The patient's height, and weight were not reported. The patient's pre-existing medical conditions included: The patient had no previous underlining or pre-existing health conditions. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: Unknown, expiry :unknown) dose was not reported, start therapy date were not reported, 1 total, administered for prophylactic vaccination. The batch number was not reported. Per procedure, no follow-up will be requested for this case. No concomitant medications were reported. It was reported that the vaccine resulted in a severe reaction, placing the patient in a life-threatening position. Approximately 6-7 days after receiving the vaccine with having no previous underlining or pre-existing health conditions his symptoms worsened. He was having severe issues.  Malaise set in, decreased appetite, dry cough along with other symptoms. The patient went to emergency department (ED) and was discharged home with unspecified antibiotics, an unspecified antispasmodic & was negative for corona virus disease (COVID). He went home for 2 days after spending the night in the ER. No signs of improvement, he just progressively getting worse and had bilateral lower extremity edema setting in. On 08-AUG-2021 he went back to the ED and was hospitalized back again after nothing had improved. Though he did not feel well another concern was the prolonged sitting in the same spot not moving about or getting up, he could very well develop a deep vein thrombosis (DVT), not to mention anemia. He went back to the ED and was hospitalized back again on 08-AUG-2021 after nothing had improved. His labs were drawn and his platelet levels had dropped to a critical value needing a platelet transfusion. Most of the labs were within normal range (WNR), however his platelets barely increased causing concern, thus dropping down again. The chest computerized tomogram (CT) was remarkable for bilateral pulmonary embolisms as well as an ultrasound (US) on his lower extremities, which confirmed a DVT in one of his legs. Specialists were consulted due the concern that his body was attacking & destroying the platelets that had been infused yet it was baffling to all that most of his other labs were "okay". His hemoglobin and hematocrit levels did drop but not enough to need a transfusion despite the prolonged bleeding. It was concluded that he was indeed suffering from vaccine induced thrombotic thrombocytopenia with symptomatic disseminated intravascular coagulation. Two rounds of IVIG (immunoglobulin) were given along with low dose anticoagulants to help dissolve the clots. He had been in the hospital sitting in the ICU with a foley catheter, unspecified intravenous (IV's), oxygen, some leg compression device and a ton of leads stuck to his body being monitored. He had multiple CT scans, multiple ultrasounds, an echocardiogram, an unspecified transfusion, lab work done daily. He had blood clots in his leg and in both lungs, he was short on breath and tired. Never he had been so sick. It turns out that everything he was going through was a severe reaction to the COVID19 vaccine. He was in the hospital living through those concerns right now. After spending 6 days in the intensive care unit (ICU)/ progressive care unit (PCU) they were able to get him discharged and bring him home to continue the current regimen he was on while hospitalized. Treatments would continue for months. The battle continued, but they were hopeful. Since his platelets have increased significantly after receiving 2 rounds of IVIG & most of the other labs were WNR, and other diagnostic studies were unremarkable. They still need to complete the Magnetic Resonance Venography (MRV) scan as an out-patient. He regained a good amount of his strength; he was not 100% but he could get up and move around and he had graduated from a walker to a cane. He had to use the cane as his balance was still a bit off and he could not afford to fall since he was on unspecified blood thinners. He still had blood clots in both of his lungs and his leg. The clots in his lungs make it difficult to breath and he had a cough that comes on quick if he talked too much. He got winded and tired very quickly if he move around too much and he needed to sit back down. His heart was also enlarged due to the extra work it has to do pushing blood through partially blocked vessels in his lungs. The effect was that he felt really cyst and his heart began to race so again he need to sit and rest. He also had a new lump appear on his leg that he was unsure as to what it was, initial concern was another clot. He had an ultrasound done to check it and he was awaiting the results. The doctors after further inspection thought it might be a cyst of some sort. He had multiple appointments with specialists over the next few weeks as follow-ups to his hospital stay. In the meantime, he had to wait for his body to break down the clots which he was told would take months. Treatment medications (dates unspecified) included: platelets, unspecified blood thinners, anticoagulants, and IVIG and his treatment included foley catheter, unspecified intravenous (IV's), oxygen, some leg compression device and a ton of leads stuck to his body being monitored. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient had not recovered from vaccine-induced thrombotic thrombocytopenia, disseminated intravascular coagulation, cyst of some sort, balance was still a bit off, deep vein thrombosis, thrombocytopenia, bilateral pulmonary embolism, malaise, and decreased appetite, and the outcome of heart was enlarged was not reported. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0: 20210916371-COVID-19 VACCINE AD26.COV2.S- Disseminated intravascular coagulation, Heart was enlarged, Cyst of some sort, Balance was still a bit off, Decreased appetite. This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s). 20210916371-COVID-19 VACCINE AD26.COV2.S- Vaccine-induced thrombotic thrombocytopenia, Thrombocytopenia, Bilateral pulmonary embolism, Deep vein thrombosis, Malaise. This event(s) is labeled per RSI and is therefore considered potentially related.