BLOOD CLOT IN LEG; SHORTNESS OF BREATH; HEART RATE INCREASED; GANGRENE IN TOE; RIGHT LEG SWOLLEN; RIGHT FOOT SWOLLEN; CHILLS; RUNNY NOSE; FEELING HOT; This spontaneous report received from a patient concerned a 50 year old male. The patient's height and weight were not reported. The patient's concurrent conditions included high blood pressure and diabetes.  The patient received COVID-19 vaccine Ad26.CoV2.S (suspension for injection, route of administration not reported, batch number 1802070, expiry date unknown), dose not reported, 1 total administered on 19-APR-2021 for prophylactic vaccination on left arm. Concomitant medications included amlodipine besilate for drug used for unknown indication, empagliflozin for drug used for unknown indication, fenofibrate for drug used for unknown indication, insulin aspart for drug used for unknown indication, insulin glargine for drug used for unknown indication, losartan for drug used for unknown indication, and pioglitazone hydrochloride for drug used for unknown indication. On an unspecified date (reported as 22-MAR-2021; 28 days prior to vaccination), the patient experienced shortness of breath, heart rate increased, runny nose, chills and was hospitalized (date unspecified). He reported that on this past Saturday, 17-APR-2021 (2 days prior to vaccination), he went to the emergency room. He reported that his toenails were coming off, the skin on his toes was coming off, and he had swelling in his right foot and up his leg. He says there was no circulation going to his toe and he was diagnosed with having a blood clot in his right leg. He says he had surgery to open up the arteries in his leg, and also reported gangrene in his toe. The subject was discharged on 21-APR-2021. On 23-APR-2021, the patient experienced feeling hot. He also reported that he may need to have his right pinky (fifth) toe amputated because it has gangrene. He reported that he is going to go back to the hospital, to which he would seek medical attention if he was having issues. Treatment medications (dates unspecified) included paracetamol. When called back due to his vaccination dates being after event start dates, the patient said that his memory is not too good, so he 'had to take his time to remember the correct dates'. The action taken with COVID-19 vaccine Ad26.CoV2.S was not applicable. The patient was recovering from blood clot in leg, and had not recovered from runny nose, shortness of breath, heart rate increased, chills, feeling hot, gangrene in toe, right leg swollen, and right foot swollen. This report was serious (caused hospitalization).; Sender's Comments: V0:  This 50-year-old  hypertensive and diabetic male patient reported that he was feeling hot and may need to have his fifth toe amputated because it has gangrene 4 days after receiving COVID-19 VACCINE AD26.COV2.S for the prevention of symptomatic SARS-CoV-2 virus infection and 2 days after discharge form the hospital.  The patient was hospitalized for shortness of breath, heart rate increased, runny nose, and chills 28 days prior to vaccination.  The patient went to the emergency room 2 days prior to vaccination because his toenails/skin on his toes were coming off, swelling in his right foot and up his leg, gangrene in his toe; he reported that there was no circulation going to his toe and was diagnosed with having a blood clot in his right leg; the patient reported he had surgery to "open up" the arteries in his leg. Four days after vaccination, the patient felt hot and reported reported that he may need to have his right pinky (fifth) toe amputated because it has gangrene.  The patient is taking paracetamol as treatment.  No other details was reported.  Based on the lack of temporal association, the causality is considered not related for the events blood clot in leg, shortness of breath, heart rate increased, right leg swelling, right foot swelling, chills, and runny nose.  The information available regarding event gangrent of fifth toe and feeling hot precludes a complete and meaningful assessment.  However, considering the temporal relationship and recently evolving theories in the literature about COVID infections and vaccinations, potential vaccine contribution cannot be excluded.  Additional information was requested.