Sadle embolism in lungs; DVT in left leg; Slight fever; Extreme fatigue; Shortness of breath,struggling for every breath; Low o2 sat; A spontaneous report was received from a health care professional, who was a 73-year-old, female patient who received Moderna's COVID-19 Vaccine (mRNA-1273) and experienced shortness of breath, slight fever, extreme fatigue, left leg deep vein thrombosis (DVT), and saddle pulmonary embolism (PE).   The patients' medical history was not provided. No concomitant medications list was provided.   On 24 Dec 2020, prior to the onset of symptoms, patient received the first of two planned doses of mRNA-1273 (Batch number 011J20A) for the prophylaxis of COVID -19 infection.  On 25 Dec 2020, patient experienced shortness of breath with low oxygen saturation levels.   On 26 Dec 2020, the patient's oxygen saturation levels were down to 89% with slight fever and extreme fatigue.   On 27 Dec 2020, patient's energy was back to normal.   On 28 Dec 2020, the patient woke up in the morning with symptoms of almost could not breathe, could not walk across the room.  The patient's vital signs included oxygen saturation 83%.  The patient was struggling for every breath.  The patient tested negative for COVID-19.  On 30 Dec 2020, another COVID-19 test was negative.  On 31 Dec 2020, patient's vital signs included oxygen saturation closer to 90%, and she reported getting better. Symptoms remained the same for about a week.  On 08 Jan 2021, the patient experienced left ankle and foot swollen. The patient was seen by physician and then sent to emergency room where it was determined that the patient had DVT in the left leg. A computerized tomogram (CT) scan found clots in the left lung, or saddle PE.  On 09 Jan 2021, the patient was discharged from the hospital.  Treatment for the events experienced included intravenous heparin and blood thinners.   Action taken with planned second dose of mRNA-1273 in response to the events was not provided.  The event, extreme fatigue, was considered resolved on 27 Dec 2020. The outcome of the events, shortness of breath, slight fever, DVT and saddle PE were not provided.  Follow-up received on 19 Jan 2021 included updated events (DVT and saddle PE), updated event details, treatment, and hospitalization details.; Reporter's Comments: This spontaneous report refers to a case of 73- year-old female patient who experienced serious event of pulmonary embolism and deep vein thrombosis and non-serious events of shortness of breath, oxygen saturation levels were down to 89% with slight fever and extreme fatigue the next day after administration of the first dose of mRNA-1273, lot # 011J20A, expiration date-unknown. Based on temporal information provided and the known safety profile of the vaccine and the absence of any other etiology factors, a causal association between the vents of shortness of breath, oxygen saturation levels were down to 89% with slight fever and extreme fatigue and the administration of  mRNA-1273 vaccine cannot be excluded. Fever and fatigue are consistent with the known safety profile of mRNA-1273 vaccine.  There is no enough information t clinically assess the causal association between the events of pulmonary embolism and deep vein thrombosis as the patient's medical history and list of concomitant medications were lacking. Main field defaults to possibly related'