IMMUNE THROMBOCYTOPENIA PURPURA; MUSCLE SORENESS AT THE ADMINISTRATION SITE; This spontaneous report was received from literature. This report concerned a 63 year old female. The objective of study was to assess causal or coincidental relationship between Immune-Mediated thrombocytopenia and COVID-19 vaccination. The patient's height, and weight were not reported. The patient's past medical history included: total hysterectomy, and concurrent conditions included: cervical cancer. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin was not reported) 1 total, dose, start therapy date were not reported for prophylactic vaccination. The batch number was not reported and has been requested. No concomitant medications were reported. It was reported that, the patient did not experience any major side effects after her vaccination except for muscle soreness at the administration site. She did not have fever, chills, shortness of breath, or recent infections. A week later (unspecified), the patient went for a routine dental checkup which was unremarkable. The patient started experiencing bleeding in her gums and was presented to the hospital. The patient later had sudden onset nose bleeds which prompted her to go to the emergency department. On presentation to the emergency department, the patient was hemodynamically stable and afebrile. Her bleeding had resolved. On an unspecified date, the patient was diagnosed with immune thrombocytopenia purpura (ITP). The complete blood count showed hemoglobin 12.2 g/dL, hematocrit 36.3 percent, white blood white blood cell count 10.9 x10exp3 cells/microL, and significant severe thrombocytopenia 2x10exp9/L, her international normalized ratio was 1.02, with a prothrombin time of 13.5 seconds and a partial thromboplastin time of 27.0 seconds. The hemolytic workup was completed with lactate dehydrogenase 150 U/L, haptoglobin 192 mg/dL, and D-dimer was 0.76. On admission, the patient received 2 units of platelets. She was also given a one time dose of prednisone 60 mg orally. Her repeat platelet count post transfusion improved to 14x10exp9 /L. The hematology was consulted and recommended starting the patient on immune globulin (human) infusion intravenously and dexamethasone 20 mg daily. Throughout admission, the patient's platelet count steadily increased. She did not have further bleeding episodes and did not require additional platelet transfusions. The testing for HIV and hepatitis B and C was negative. The patient's heparin-induced platelet IgG antibody was negative. Imaging including ultrasound Doppler of the abdomen/pelvis, ultrasound Doppler of upper and lower extremities, magnetic resonance venogram of the head, and computed tomography angiography of the thorax showed no evidence of thrombosis. The patient remained hemodynamically stable throughout admission with no signs of active bleeding. She was ultimately deemed stable for discharge 5 days after admission, with a platelet count of 252x10exp9 /L. The number of days of hospitalization was reported as 5. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient was recovering from immune thrombocytopenia purpura, and the outcome of muscle soreness at the administration site was not reported.  The Authors discussed to the best of their knowledge, this was the first case of an individual with no other identifiable cause experiencing ITP after receiving the Ad26.COV2.S (Janssen; Johnson & Johnson) vaccine. The possibility of vaccination triggered de novo ITP could not be excluded; however, the abrupt occurrence 17 days after vaccine administration and a severe drop in platelets to 2 x 10exp9 /L raise concern for drug-induced thrombocytopenia.  The Authors believed with widespread distribution and administration of the COVID-19 vaccine, additional surveillance and analysis of data are needed to determine the true correlation or causation of severe thrombocytopenia after vaccination. This report was serious (Hospitalization Caused / Prolonged, and Life Threatening).; Sender's Comments: V0:20210911676-COVID-19 VACCINE AD26.COV2.S- Immune thrombocytopenia purpura. 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).