4 blood clots, 2 in each lung; I felt sore; Tired; Feverish; This spontaneous case was reported by a patient and describes the occurrence of PULMONARY THROMBOSIS (4 blood clots, 2 in each lung) in a 65-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Patient had no family history of blood clots, no cancer or pain or swelling in the legs.     In November 2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In November 2021, the patient experienced PAIN (I felt sore), FATIGUE (Tired) and PYREXIA (Feverish). On an unknown date, the patient experienced PULMONARY THROMBOSIS (4 blood clots, 2 in each lung) (seriousness criterion medically significant). The patient was treated with ENOXAPARIN SODIUM (LOVENOX [ENOXAPARIN SODIUM]) (subcutaneous) ongoing since an unknown date for Pulmonary thrombosis, at an unspecified dose and frequency. In November 2021, PAIN (I felt sore), FATIGUE (Tired) and PYREXIA (Feverish) had resolved. At the time of the report, PULMONARY THROMBOSIS (4 blood clots, 2 in each lung) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In November 2021, Heart rate: elevated (High) Elevated. On an unknown date, Computerised tomogram: showed 4 blood clots, 2 in each lung (abnormal) Showed 4 blood clots, 2 in each lung. On an unknown date, Fibrin D dimer: results not reported Results not reported.         Concomitant product use was not provided by the reporter.  Patient had 2 initial inoculations of the vaccine, and received third booster in November. On the very day of booster vaccination the patient felt sore, tired and feverish for about a day. On the second day, the patient noticed the heart rate was elevated. So patient tried to rest to get it back to normal, however it was still stayed elevated. Patient was advised to go the ER (emergency room). At first the ER Physician thought it was just a reaction to the vaccine. However upon the test result of the D-dimer, it was advised to have a CT scan. The patient was put Lovenox sub and on blood thinners.  Company comment: This is a spontaneous case concerning a 65-year-old, male patient with no reported medical history and with vaccine history of receiving 2 doses of mRNA-1273 vaccine, who experienced the unexpected serious (medically significant) AESI event of pulmonary thrombosis and unexpected non-serious event of pain and the expected non-serious events of fatigue and pyrexia. The event pain, fatigue and pyrexia occurred after the third dose of mRNA-1273 vaccine. The event pulmonary thrombosis occurrence unknown with respect to the third dose of mRNA-1273 vaccine administration. The event pulmonary thrombosis was described as, patient experienced persistent elevated heart rate. Patient sought ER consult. D-dimer test was done and due to unspecified result CT scan was performed which showed 4 blood clots, 2 in each lung. Patient was treated with Enoxaparin (Levonox) subcutaneous and was put on blood thinners. It was reported that the patient has no family history of blood clots and cancer. No pain or swelling in the legs. No other information surrounding the events was reported. The outcome of the events pain, fatigue and pyrexia was reported as resolved while the event pulmonary thrombosis the outcome was unknown. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 65-year-old, male patient with no reported medical history and with vaccine history of receiving 2 doses of mRNA-1273 vaccine, who experienced the unexpected serious (medically significant) AESI event of pulmonary thrombosis and unexpected non-serious event of pain and the expected non-serious events of fatigue and pyrexia. The event pain, fatigue and pyrexia occurred after the third dose of mRNA-1273 vaccine. The event pulmonary thrombosis occurrence unknown with respect to the third dose of mRNA-1273 vaccine administration. The event pulmonary thrombosis was described as, patient experienced persistent elevated heart rate. Patient sought ER consult. D-dimer test was done and due to unspecified result CT scan was performed which showed 4 blood clots, 2 in each lung. Patient was treated with Enoxaparin (Levonox) subcutaneous and was put on blood thinners. It was reported that the patient has no family history of blood clots and cancer. No pain or swelling in the legs. No other information surrounding the events was reported. The outcome of the events pain, fatigue and pyrexia was reported as resolved while the event pulmonary thrombosis the outcome was unknown. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.