Post-COVID-19 Vaccine Thromboembolic Complication in the Setting of Newly Diagnosed May-Thurner Syndrome.

May-Thurner syndrome (MTS) can lead to deep venous thrombosis (DVT) in the left lower extremity, and it is often triggered by factors such as surgery or pregnancy. We present a rare case where the risk factor for thromboembolism in MTS is a complication from COVID-19 vaccination. A 44-year-old female who presented with fatigue, fever, and myalgia had developed thromboembolism as a complication of the Johnson & Johnson COVID-19 vaccine. Diagnostic criteria for vaccine-induced immune thrombotic thrombocytopenia (VITT) should be considered in such cases that include symptoms within 5-30 days post vaccination, elevated D-dimer, and thrombosis. Treatment involved anticoagulants and intervention for MTS included thrombectomy and stent placement. Recognition of post-COVID-19 vaccination complications such as VITT is crucial for early intervention and patient awareness during vaccination decisions.