Covishield vaccination and pulmonary thromboembolism: A coincidence or a causal association?

With the eruption of COVID pandemic, many cases of thromboembolic events in association with the COVID infection were reported suggesting the prothrombotic state associated with the infection. After a few years, eventually some of the COVID vaccines came into implementation. With the discovery and implementation of COVID vaccinations, a very few cases have been reported to have developed thromboembolic events, including pulmonary thromboembolism. Different types of vaccines have been associated with different rates of thromboembolic events. Covishield vaccine is rarely associated with thrombotic complications. In the case report below, we present a case summary of a young married female, who presented with shortness of breath a week after the Covishield vaccination and presented to our tertiary care center with further worsening of symptoms during a course of 6 months. On detailed workup, she was diagnosed to have a large pulmonary thrombus affecting the left main pulmonary artery. Other possible etiologies of the hypercoagulable states were ruled out. Though COVID vaccines are known to induce prothrombotic state in the body, we could not be sure if it was the actual cause for the pulmonary thromboembolism or just a coincidence.