PULMONARY EMBOLISM; HAEMOPERITONEUM; MESENTERIC HAEMORRHAGE; SPLENIC HAEMORRHAGE; SPLENIC RUPTURE; SPLENIC THROMBOSIS; SPLENOMEGALY; LEFT UPPER QUADRANT/ABDOMINAL PAIN; DYSPNOEA; This spontaneous report received from a physician concerned a 53 years old female The patient's height, and weight were not reported. The patient had no known allergies.  The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, intramuscular, batch number: 1805029, and expiry: UNKNOWN) dose was not reported, 1 total administered on 16-MAR-2021 for prophylactic vaccination. Concomitant medications included Centrum Multi-Gummies for Women.  On an unspecified date in MAR-2021 the patient began to experience slowly progressive shortness of breath; on 01-APR-2021 she had left upper quadrant pain. On 03-APR-2021 the patient presented to the emergency room.  Laboratory data included: Pulmonary Angiogram/CT Chest - abnormal and computerised tomogram abdomen/pelvis at 09:37, showed segmental and subsegmental pulmonary emboli in the lower lobes of both lungs. Small volume perisplenic hemorrhage and small volume pneumoperitoneum in the pelvis or findings concerning for spontaneous splenic rupture and moderately enlarged spleen. Additional CT abdomen and pelvis with IV contrast at 23:05 showed: Small to moderate amount of hemoperitoneum, slightly increased since the earlier study. There is definitely new blood adjacent to the liver. The hemorrhage adjacent to the spleen appears similar to the earlier study. Due to the timing of the scans with relation to the contrast injection, the physician could not confirm a splenic laceration, although it was suspected to be the source of hemorrhage. Small amount of mesenteric blood was slightly increased. Continuous heparin infusion was started for bilateral pulmonary embolism. On 04-APR-2021, an inferior vena cava filter was placed and patient was vaccinated with Acthib (HIB Vaccine), Bexsero (meningococcal vaccine) and Prevnar (pneumococcal vaccine) in anticipation of splenectomy. On 07-APR-2021, a laparoscopic splenectomy was performed. The spleen was evaluated by pathology which reported that organizing blood clot on surface was consistent with rupture. No evidence of malignancy was reported.  The patient was also treated with anticoagulant therapy (dates unspecified). The patient remained inpatient while recovering from surgery.  On 12-APR-2021, the patient was transitioned to rivaroxaban for therapeutic anticoagulation. Patient remained hospitalized as of 12-APR-2021.  The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient had not recovered from pulmonary embolism, haemoperitoneum, mesenteric haemorrhage, splenic haemorrhage, splenic rupture, splenic thrombosis, splenomegaly, dyspnoea, abdominal pain upper, and left upper quadrant/abdominal pain. This report was serious (Hospitalization Caused / Prolonged, Disability Or Permanent Damage).; Sender's Comments: V0:  This 53-year-old female patient of unspecified ethnicity was found to  have pulmonary embolism and spontaneous splenic rupture 18 days after receiving COVID-19 VACCINE AD26.COV2.S for the prevention of symptomatic SARS-CoV-2 virus infection.  No concurrent illness and medical history reported. Emergency room consult for slowly progressive shortness of breath and left upper quadrant pain that starts on an unspecified date after vaccination.   Pulmonary Angiogram/CT Chest showed segmental and subsegmental pulmonary emboli in the lower lobes of both lungs; small volume perisplenic hemorrhage and small volume pneumoperitoneum in the pelvis; moderately enlarged spleen with findings concerning for spontaneous splenic rupture.  CT abdomen and pelvis with IV contrast showed small to moderate amount of hemoperitoneum, slightly increased since the earlier study; definite new blood adjacent to the liver.  Continuous heparin infusion was started; vaccinated with Acthib (HIB Vaccine), Bexsero (meningococcal vaccine) and Prevnar (pneumococcal vaccine).  Laparoscopic splenectomy was done 22 days after vaccination; pathology report is consistent with splenic rupture with no evidence of malignancy.  The patient was shifted to rivaroxaban.  No other details reported. The information available regarding splenic rupture precludes a complete and meaningful assessment.  Based on the information that is available, the event pulmonary embolism is assessed as plausible with the causal association to immunization, per WHO causality classification of adverse events following immunization based on a lack of a definitive plausible biological mechanism; considering the temporal relationship and recently evolving theories in the literature about COVID infections and vaccinations, the potential vaccine contribution cannot be excluded.  Additional information was requested.