blood clot in leg; double heart attack; blood clot in his leg that traveled to his heart and lungs; This case was received via an unknown source (no reference has been entered for a health authority or license partner) on 02-Dec-2021 and was forwarded to Moderna on 02-Dec-2021.    This spontaneous case was reported by a consumer and describes the occurrence of VENOUS THROMBOSIS LIMB (blood clot in leg), MYOCARDIAL INFARCTION (double heart attack) and PULMONARY EMBOLISM (blood clot in his leg that traveled to his heart and lungs) in a 54-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 008C21A and 019B21A) for COVID-19 vaccination.     Concurrent medical conditions included Arthritis.   On 26-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 23-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 07-Nov-2021, the patient experienced VENOUS THROMBOSIS LIMB (blood clot in leg) (seriousness criterion medically significant), MYOCARDIAL INFARCTION (double heart attack) (seriousness criterion medically significant) and PULMONARY EMBOLISM (blood clot in his leg that traveled to his heart and lungs) (seriousness criterion medically significant). The patient was treated with RIVAROXABAN (XARELTO) for Clot blood, at a dose of 20 mg once a day and HYDROCHLOROTHIAZIDE for Blood pressure, at a dose of 12.5 mg once a day. At the time of the report, VENOUS THROMBOSIS LIMB (blood clot in leg), MYOCARDIAL INFARCTION (double heart attack) and PULMONARY EMBOLISM (blood clot in his leg that traveled to his heart and lungs) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered PULMONARY EMBOLISM (blood clot in his leg that traveled to his heart and lungs) to be related. No further causality assessments were provided for VENOUS THROMBOSIS LIMB (blood clot in leg) and MYOCARDIAL INFARCTION (double heart attack).    Concomitant product use was not provided by the reporter.  Company Comment: This spontaneous case concerns a 54-year-old, male patient with relevant medical history of Arthritis, who experienced the unexpected, serious AESI of venous thrombosis limb, myocardial infarction and pulmonary embolism. The events occurred 6 months, 15 days after administration of the second dose of the Moderna mRNA-1273 vaccine. The patient underwent Orthoscopic Knee Replacement surgery on 07Nov2021. During the surgery, while he was under anesthesia, the patient had a blood clot in his leg which traveled to his heart and lungs and caused a 'double heart attack'. The patient's Orthopedic surgeon mentioned that he has never seen such condition in 27 years. Laboratory test/s were not provided. However, he was treated with Xarelto (rivaroxaban) 20 mg daily for blood clot and hydrochlorothiazide 12.5 mg daily for blood pressure. The outcomes of the events were was unknown at the time of the report. The rechallenge was not applicable as the events occurred after the second dose. The medical history of Arthritis, which is related to long-term inflammation and may cause cardiovascular disease which increases the risk for thromboembolic events, remains a confounder. The benefit-risk relationship of the Moderna mRNA-1273 vaccine is not affected by this report. Further information has been requested.   This case was linked to MOD-2021-403394, MOD-2021-403395 (Patient Link).; Sender's Comments: This spontaneous case concerns a 54-year-old, male patient with relevant medical history of Arthritis, who experienced the unexpected, serious AESI of venous thrombosis limb, myocardial infarction and pulmonary embolism. The events occurred 6 months, 15 days after administration of the second dose of the Moderna mRNA-1273 vaccine. The patient underwent Orthoscopic Knee Replacement surgery on 07Nov2021. During the surgery, while he was under anesthesia, the patient had a blood clot in his leg which traveled to his heart and lungs and caused a 'double heart attack'. The patient's Orthopedic surgeon mentioned that he has never seen such condition in 27 years. Laboratory test/s were not provided. However, he was treated with Xarelto (rivaroxaban) 20 mg daily for blood clot and hydrochlorothiazide 12.5 mg daily for blood pressure. The outcomes of the events were was unknown at the time of the report. The rechallenge was not applicable as the events occurred after the second dose. The medical history of Arthritis, which is related to long-term inflammation and may cause cardiovascular disease which increases the risk for thromboembolic events, remains a confounder. The benefit-risk relationship of the Moderna mRNA-1273 vaccine is not affected by this report. Further information has been requested.