pulmonary embolism; This spontaneous case was reported by a patient family member or friend and describes the occurrence of PULMONARY EMBOLISM (pulmonary embolism) in a 49-year-old male patient who received mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (batch no. 204F23-2A) for COVID-19 prophylaxis.     Previously administered products included for COVID-19 prophylaxis: Moderna COVID-19 Vaccine (Dose 1, lot number 030M20A) in 2021, Moderna COVID-19 Vaccine (Dose 2, lot number 031A21A) in 2021, Moderna COVID-19 Vaccine (Dose 3 and lot number 939904) on 24-Oct-2021; for Product used for unknown indication: Flu vaccine on 01-Sep-2023. Past adverse reactions to the above products included No adverse event with Flu vaccine, Moderna COVID-19 Vaccine, Moderna COVID-19 Vaccine and Moderna COVID-19 Vaccine. Concurrent medical conditions included Hypogonadism. Concomitant products included TESTOSTERONE ENANTHATE (XYOSTED) for Hypogonadism.    On 03-Oct-2023, the patient received fourth dose of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (unknown route) 1 dosage form. On 19-Oct-2023,  after starting mRNA-1273.815 (SPIKEVAX 2023-2024 PFS), the patient experienced PULMONARY EMBOLISM (pulmonary embolism) (seriousness criterion medically significant). The patient was treated with APIXABAN (ELIQUIS) on 06-Nov-2023 at a dose of 10 milligram twice a day. At the time of the report, PULMONARY EMBOLISM (pulmonary embolism) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Computerised tomogram: contrast was done and that was when they found the multiple bilateral pulmonary embolism. But there were no DVTs detected.. On an unknown date, Fibrin D dimer: very elevated (4000)..     For mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) (Unknown), the reporter did not provide any causality assessments.   Patient's wife reported that her husband will be worked up regarding other issues, but they just wanted to make sure that they are doing their due diligent. He initially went to an urgent care where they found that his D-dimer was very elevated (4000). Patient was then referred to an emergency room where CT scan with contrast was done and that was when they found the multiple bilateral pulmonary embolisms. But there were no DVTs detected. Patient was kept overnight and was discharged with Eliquis to be taken 10 mg twice a day then starting today, 06-Nov-2023 and will be tapered to 5 mg twice a day. Echocardiogram was done to check the LV function and some more lab works. Patient was not recommended to fly back to their home until 03-Nov-2023. Caller stated that the husband's symptoms pretty much started on 19-Oct-2023 when he felt he was not feeling well. He had an appointment where work up for possible clotting disorders will be done on 15-Nov-2023.  Company Comment: This is a spontaneous case concerning a 49-year-old male patient with a history of use of Testosterone as concomitant medication, who experienced the serious (due to medically significant) unexpected, AESI event of Pulmonary embolism, which occurred approximately 15 days after a dose of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) vaccine, received as the fourth dose of COVID-19 vaccination schedule. It was reported that patient initially went to an urgent care where they found that his D-dimer was very elevated (4000). Patient was then referred to an emergency room where CT scan with contrast was done and that was when they found the multiple bilateral pulmonary embolisms. But there were no DVTs detected. Patient was kept overnight and was discharged with Eliquis to be taken 10 mg twice a day. Echocardiogram was done to check the LV function and some more lab works. He had an appointment where work up for possible clotting disorders will be done. The mentioned medical history could be a risk factor for the event. The benefit-risk relationship of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) vaccine is not affected by this report.; Sender's Comments: Company Comment: This is a spontaneous case concerning a 49-year-old male patient with a history of use of Testosterone as concomitant medication, who experienced the serious (due to medically significant) unexpected, AESI event of Pulmonary embolism, which occurred approximately 15 days after a dose of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) vaccine, received as the fourth dose of COVID-19 vaccination schedule. It was reported that patient initially went to an urgent care where they found that his D-dimer was very elevated (4000). Patient was then referred to an emergency room where CT scan with contrast was done and that was when they found the multiple bilateral pulmonary embolisms. But there were no DVTs detected. Patient was kept overnight and was discharged with Eliquis to be taken 10 mg twice a day. Echocardiogram was done to check the LV function and some more lab works. He had an appointment where work up for possible clotting disorders will be done. The mentioned medical history could be a risk factor for the event. The benefit-risk relationship of mRNA-1273.815 (SPIKEVAX 2023-2024 PFS) vaccine is not affected by this report.