BLOOD CLOT IN UPPER THIGH; NO PULSE FROM KNEE DOWN ON  RIGHT LEG; RINGING AND BUZZING IN EARS; PURPLE TOE; COULD NOT MOVE; FEELING CRAPPY; TIRED; NAUSEOUS; This spontaneous report received from a patient concerned a 58 year old male. The patient's height, and weight were not reported. The patient's concurrent conditions included Barrett's esophagus, and controlled high blood pressure. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, intramuscular batch number: 1805031, and expiry: unknown) dose was not reported, 1 total administered in left arm on 24-MAR-2021 for prophylactic vaccination. Concomitant medications included Nexium (esomeprazole sodium) for Barrett's esophagus, and lisinopril for high blood pressure.  On 25-MAR-2021, the day after the vaccination, patient felt crappy and could not move, had tiredness and nauseous. After 10 to 12 days of vaccination on an unspecified date in APR-2021, the patient had ringing and buzzing in ears, pain in the bottom of feet on walking, and purple discoloration to front of the right toe. The patient had visited health care professional (HCP). The patient had undergone some tests and HCP identified no pulse from the knee down on his right leg and a blood clot in upper thigh. The patient had experienced pins and needles and buzzing on his leg. He has also has a ringing and a buzzing in his ears and the bottom of his feet hurt when he walked on them. The patient was scheduled for an appointment with cardiovascular surgeon on 28-APR-2021, prior to the visit the patient has to tested negative for COVID. The patient went to take test on 23-APR-2021 and results not yet received. Laboratory data included: Peripheral pulse absent (NR: not provided) no pulse from the knee down on right leg.  The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The outcome of the feeling crappy, tired, nauseous, no pulse from knee down on right leg, blood clot in upper thigh, ringing and buzzing in ears and could not move was not reported. This report was serious (Other Medically Important Condition). This case, from the same reporter is linked to.This spontaneous report received from a patient concerned a 58 year old male.; Sender's Comments: V0:  This 58-year-old male patient was found to have blood clot in upper thigh with no pulse from the knee down 10 to 12 days after receiving COVID-19 VACCINE AD26.COV2.S for the prevention of symptomatic SARS-CoV-2 virus infection.  Concurrent conditions include Barret's esophagus and "controlled" high blood pressure; concomitant medications includes Nexium and lisinopril.  The symptoms reported were ringing and buzzing in ears, pain in the bottom of feet on walking, pins and needles and buzzing on his leg, and purple discoloration to front of the right toe that prompted consult with HCP, who advised the patient that there was no pulse from the knee down on his right leg and a blood clot in upper thigh.  Prior COVID test was negative.  No other details reported.  The information available 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.