Immune thrombocytopenia purpura/immune thrombocytopenic purpura (ITP); injection site myalgia; This literature-non-study case was reported in a literature article and describes the occurrence of IMMUNE THROMBOCYTOPENIA (Immune thrombocytopenia purpura/immune thrombocytopenic purpura (ITP)) in a 68-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.   LITERATURE REFERENCE:    The patient's past medical history included Primary hyperaldosteronism. Previously administered products included for Influenza: influenza vaccine. Past adverse reactions to the above products included No adverse event with influenza vaccine. Concurrent medical conditions included Hypothyroidism, Osteoporosis and Migraine headache. Concomitant products included LEVOTHYROXINE, POTASSIUM CHLORIDE, CALCIUM CARBONATE, ERGOCALCIFEROL (CALCIUM AND VITAMIN D), RALOXIFENE, SPIRONOLACTONE and SUMATRIPTAN for an unknown indication.    In 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced INJECTION SITE PAIN (injection site myalgia). On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced IMMUNE THROMBOCYTOPENIA (Immune thrombocytopenia purpura/immune thrombocytopenic purpura (ITP)) (seriousness criteria hospitalization and medically significant). The patient was treated with IMMUNOGLOBULINS NOS (IMMUNOGLOBULIN I.V) (intravenous) for Immune thrombocytopenic purpura, at a dose of 1 gram per kilogram, 2 doses and PREDNISONE (oral) for Immune thrombocytopenia, at a dose of 60 milligram once a day. In 2021, INJECTION SITE PAIN (injection site myalgia) had resolved. At the time of the report, IMMUNE THROMBOCYTOPENIA (Immune thrombocytopenia purpura/immune thrombocytopenic purpura (ITP)) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood albumin: Normal. On an unknown date, Blood bilirubin: Normal. On an unknown date, Blood electrolytes: Normal. On an unknown date, Blood smear test: Peripheral blood smear showed normal morphology of blood cells and no schistocytes.. On an unknown date, Epstein-Barr virus test: (Negative) Negative. On an unknown date, Glomerular filtration rate: Normal. On an unknown date, HIV test: (Negative) HIV 1, HIV 2 was negative. On an unknown date, Haematocrit: 34.1 %. On an unknown date, Haemoglobin: 11.9 g/dL. On an unknown date, Haptoglobin: Normal. On an unknown date, Hepatitis B virus test: (Negative) Negative. On an unknown date, Hepatitis C virus test: (Negative) Negative. On an unknown date, Liver function test: Normal. On an unknown date, Physical examination: diffuse petechial rash most notably on bilateral lower legs but also present on bilateral arms, chest, forehead, and hard palate. There were small hemorrhagic vesicles located on the patient's fingers and on the lateral aspect of her tongue. Fresh ecchymoses on the patient's anterior legs were noted on the patient's integument examination.  On an unknown date, Platelet count: 15 10^9/L thrombocytopenia, 4 10^9/L even more profound thrombocytopenia, 14 10^9/L On day 2 of hospitalization, after the first dose of IVIG and prednisone were given, the patient's platelet count increased, 88 10^9/L On day 3 of hospitalization, after the second doses of IVIG and prednisone were given, the patient's platelet count significantly increased to and 258 10^9/L a follow-up appointment with her primary care provider as well as the hematology clinic one week after hospital discharge. On an unknown date, Protein total: Normal. On an unknown date, Vital signs measurement: unremarkable. On an unknown date, White blood cell count: 9.7 10^9/L.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered IMMUNE THROMBOCYTOPENIA (Immune thrombocytopenia purpura/immune thrombocytopenic purpura (ITP)) and INJECTION SITE PAIN (injection site myalgia) to be related.    Patient was discharged home with a 60 mg prednisone dose per day with a plan to taper over 3-4 weeks.  Seven days post-vaccination, the patient experienced a widespread petechial rash, minor bruising, and gum bleeding. These symptoms prompted her visit to a local urgent care center, where she was found on laboratory testing to have thrombocytopenia with a platelet count of 15 × 109/L. She was immediately referred to a local emergency department where repeat testing was performed, and results demonstrated an even more profound thrombocytopenia with a platelet count of 4 × 109/L. Also, has no prior history of allergies or adverse reactions to medications. Patient denied any recent illnesses or being around anyone that was ill. She denied respiratory, cardiac, gastrointestinal, and urinary symptoms. She had no personal or family history of bleeding disorders or platelet disorders. Of note, there was no evidence of splenomegaly. Other laboratory testing that were all within normal limits included electrolytes, liver function tests, estimated GFR, total protein, and albumin. Hemolytic markers such as bilirubin and haptoglobin were within normal limits. Peripheral blood smear showed normal morphology of blood cells and no schistocytes. Clinical presentation and laboratory findings were consistent with immune thrombocytopenic purpura (ITP); therefore, the diagnosis of ITP was made. Secondary causes of ITP were investigated. The patient tested negative for HIV 1, HIV 2, hepatitis B virus, hepatitis C virus, and Epstein-Barr virus serology was negative for acute infection.  Patient had no history of joint pain or swelling, rashes, fatigue, and fever, suggestive of rheumatological disease.  Patient had no other reported side effects or symptoms after her vaccination other than minor injection site myalgia for about 1 day.  Reported that clinical presentation and laboratory findings were consistent with immune thrombocytopenic purpura (ITP).  Company comment: This literature-non-study case concerns a 68-year-old, female patient with no relevant medical history, who experienced the unexpected serious (hospitalization and medically significant) AESI of immune thrombocytopenia. The event occurred approximately 7 days after first dose of mRNA-1273. As reported, seven days post-vaccination, the patient experienced a widespread petechial rash, minor bruising, and gum bleeding. The patient had no personal or family history of bleeding disorders or platelet disorders. Laboratory findings showed profound thrombocytopenia 4 × 109/L with rest of the laboratory parameters as normal. Secondary causes of ITP were excluded and diagnosis of ITP  was made. Of note, there was no evidence of splenomegaly. The patient was admitted to hospital and treated with IVIG and oral prednisone with increase in platelet count and eventual normalization. The benefit-risk relationship of mRNA-1273 is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 06-Oct-2022: Live follow-up received by safety on 06-Oct-2022 has Email and contains significant information: Reporter information, literature information, medical History, lab data, concomitant medications, treatment drugs and event information were updated.; Sender's Comments: This literature-non-study case concerns a 68-year-old, female patient with no relevant medical history, who experienced the unexpected serious (hospitalization and medically significant) AESI of immune thrombocytopenia. The event occurred approximately 7 days after first dose of mRNA-1273. As reported, seven days post-vaccination, the patient experienced a widespread petechial rash, minor bruising, and gum bleeding. The patient had no personal or family history of bleeding disorders or platelet disorders. Laboratory findings showed profound thrombocytopenia 4 × 109/L with rest of the laboratory parameters as normal. Secondary causes of ITP were excluded and diagnosis of ITP  was made. Of note, there was no evidence of splenomegaly. The patient was admitted to hospital and treated with IVIG and oral prednisone with increase in platelet count and eventual normalization. The benefit-risk relationship of mRNA-1273 is not affected by this report.