Thrombotic Thrombocytopenic Purpura after Ad26.COV2-S Vaccination

The U.S. Food and Drug Administration (FDA) recently issued an Emergency Use Authorization (EUA) for two highly effective Sars-CoV-2 (COVID-19) vaccines from Pfizer-BioNTech and Moderna. More recently, EUA was granted for the Johnson and Johnson COVID-19 vaccine which uses traditional virus-based technology. In this vaccine, researchers added the gene for the coronavirus spike protein to modified Adenovirus 26 and named it Ad26.COV2-S. Nearly 7 million doses of the Ad26.COV2-S have been administered as of mid-April 2021. Recently the Federal Drug Administration and Center for Disease Control and Prevention reviewed data involving six reported cases in the United States of cerebral venous sinus thrombosis in combination with thrombocytopenia in people who received the vaccination. All cases were in women between 18 and 48, with symptoms developing six to 13 days after vaccination. A recent study in the United Kingdom reported similar events in 23 patients age 21 to 77, 61% of which were female, with cases of presumed vaccine induced thrombosis and thrombocytopenia occurring six to 24 days after vaccination. We report a 62-year-old female who presented to the emergency department (ED) with acute onset of altered mental status. She had received the Ad26.COV2-S vaccine 37 days prior to ED presentation. She developed thrombotic thrombocytopenic purpura (TTP) and no other cause was found. To our knowledge this is the first case in the United States of thrombotic thrombocytopenic purpura after receiving the Ad26.COV2-S COVID-19 vaccine.