ATRIAL FIBRILLATION; PULMONARY EMBOLISM; DEEP VEIN THROMBOSIS; PNEUMONIA; PERICARDITIS; CONSTIPATION; SEVERE CHEST PAIN THAT RADIATED UP TO SHOULDERS; MALAISE; LOW-GRADE FEVER; This spontaneous report received from a health care professional (nurse) concerned a 65 year old male. The patient's weight was 205 pounds, and height was 74 inches. The patient's past medical history included: COVID-19 in JAN-2021, and concurrent conditions included: non alcohol user, non smoker, and well controlled hypertension. The patient did not have any history of drug abuse or illicit drug use. The patient experienced drug allergy when treated with levofloxacin for drug used for unknown indication.  The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, and batch number: 204A21A expiry: UNKNOWN) dose was not reported, 1 total, administered on 03-AUG-2021 to left arm for prophylactic vaccination. Concomitant medications included amitriptyline for drug used for unknown indication, apixaban for drug used for unknown indication, colchicine for drug used for unknown indication, colecalciferol for drug used for unknown indication, ibuprofen for drug used for unknown indication, rivaroxaban for drug used for unknown indication, and metoprolol.  On 05-AUG-2021, the patient had malaise and typical low-grade fever. On 24-AUG-2021, the patient experienced severe chest pain that radiated up to shoulders. The patient went to emergency room and laboratory data included Fibrin D dimer Elevated, but the emergency room doctor said it was likely due to constipation. They also performed computerized tomogram (CT) without contrast and did not see anything. They sent patient to home, but on 30-AUG-2021, the pain came back worse than before. The patient went back to emergency room. Laboratory data included CT scan with contrast, which showed pulmonary embolism and 1 deep vein thrombosis in each leg. The patient was transferred and admitted to hospital on 30-AUG-2021. Treatment medications included: heparin drip. They thought they might had to surgically remove the pulmonary embolism, but ended up just treated medically, and was converted to Eliquis (apixaban). During the hospital admission, the patient experienced atrial fibrillation and was cardioverted. The patient was discharged from hospital on 07-SEP-2021. The patient was admitted for 8 days during first admission.  The patient was home for a week. On 13-SEP-2021, the patient experienced pneumonia and went back to hospital was re-admitted on 13-SEP-2021 with pneumonia and pericarditis (built up fluid in the pericardium). The doctors at previous hospital mentioned inflammation but they never treated it. The patient was discharged from hospital on 19-SEP-2021. The patient was admitted for 6 days during second admission. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from malaise, and low-grade fever on 09-AUG-2021, and the outcome of constipation, pulmonary embolism, deep vein thrombosis, atrial fibrillation, pneumonia, pericarditis and severe chest pain that radiated up to shoulders was not reported. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0: 20210958673 -COVID-19 VACCINE AD26.COV2.S-Pulmonary embolism, deep vein thrombosis, atrial fibrillation, pneumonia, pericarditis .This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).