Tested positive for Covid 19; Blood clot; pain in his left leg; his leg was throbbing; Left leg tingling; felt as his arm and hands were swelling up; felt as his arm and hands were swelling up; This spontaneous case was reported by a patient and describes the occurrence of THROMBOSIS (Blood clot) in a 40-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 039F21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Patient reported no allergies.  Concurrent medical conditions included Blood pressure high and Cholesterol.   On 17-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 17-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 17-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In 2021, the patient experienced PAIN IN EXTREMITY (pain in his left leg; his leg was throbbing), PARAESTHESIA (Left leg tingling), the first episode of PERIPHERAL SWELLING (felt as his arm and hands were swelling up) and the second episode of PERIPHERAL SWELLING (felt as his arm and hands were swelling up). On 02-Mar-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced THROMBOSIS (Blood clot) (seriousness criterion medically significant). On 17-Jul-2022, the patient experienced SARS-COV-2 TEST POSITIVE (Tested positive for Covid 19). At the time of the report, THROMBOSIS (Blood clot), PAIN IN EXTREMITY (pain in his left leg; his leg was throbbing), PARAESTHESIA (Left leg tingling), the last episode of PERIPHERAL SWELLING (felt as his arm and hands were swelling up) and SARS-COV-2 TEST POSITIVE (Tested positive for Covid 19) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 17-Jul-2022, SARS-CoV-2 test: (Positive) positive for Covid 19.         Concomitant medicines include pills for cholesterol levels and high blood pressure pills.  Patient reported that he does not have risks or Family history for blood clots. Patient was not sure of when this symptoms exactly started, but it was after receiving the first booster.  Treatment medicine includes blood thinners since blood clot was found. Company comment: This spontaneous case concerns a 40-year-old, male patient with history of concomitant intake of High blood pressure pills (unspecified), who experienced the unexpected, serious (medically significant) AESI of thrombosis; the unexpected, non-serious AESI of SARS-CoV-2 test positive; and other associated unexpected, non-serious events. The event thrombosis occurred approximately 3 months after receiving the third (booster) dose of the mRNA-1273 vaccine. The event SARS-CoV-2 test positive occurred 8 months after receiving the third (booster) dose of the mRNA-1273 vaccine. The start dates of the other events were not provided. It was reported that after vaccination (unknown number of days), the patient started having pain in his left leg. His leg was throbbing and tingling. He also felt as his arm and hands were swelling up. No additional details were provided until approximately 3 months after vaccination, the patient sought consultation and it was reported that a blood clot was found. No further details were provided regarding diagnostic test/s done. He was treated with unspecified anticoagulants. It was also reported that 8 months after vaccination, the patient tested positive for SARS-CoV-2. No additional symptoms were reported. The outcome of the events were unknown at the time of the report. The patient's history of an underlying medical condition (Hypertension), which is being treated with unspecified High blood pressure pills and a risk factor for COVID-19, remains a confounder for the event SARS-CoV-2 test positive. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This spontaneous case concerns a 40-year-old, male patient with history of concomitant intake of High blood pressure pills (unspecified), who experienced the unexpected, serious (medically significant) AESI of thrombosis; the unexpected, non-serious AESI of SARS-CoV-2 test positive; and other associated unexpected, non-serious events. The event thrombosis occurred approximately 3 months after receiving the third (booster) dose of the mRNA-1273 vaccine. The event SARS-CoV-2 test positive occurred 8 months after receiving the third (booster) dose of the mRNA-1273 vaccine. The start dates of the other events were not provided. It was reported that after vaccination (unknown number of days), the patient started having pain in his left leg. His leg was throbbing and tingling. He also felt as his arm and hands were swelling up. No additional details were provided until approximately 3 months after vaccination, the patient sought consultation and it was reported that a blood clot was found. No further details were provided regarding diagnostic test/s done. He was treated with unspecified anticoagulants. It was also reported that 8 months after vaccination, the patient tested positive for SARS-CoV-2. No additional symptoms were reported. The outcome of the events were unknown at the time of the report. The patient's history of an underlying medical condition (Hypertension), which is being treated with unspecified High blood pressure pills and a risk factor for COVID-19, remains a confounder for the event SARS-CoV-2 test positive. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report.