{"id":8526,"date":"2021-04-09T20:51:16","date_gmt":"2021-04-09T10:51:16","guid":{"rendered":"https:\/\/mvec.mcri.edu.au\/?post_type=references&p=8526"},"modified":"2025-05-16T10:09:00","modified_gmt":"2025-05-16T00:09:00","slug":"thrombosis-with-thrombocytopenia-syndrome","status":"publish","type":"references","link":"https:\/\/mvec.mcri.edu.au\/hi\/references\/thrombosis-with-thrombocytopenia-syndrome\/","title":{"rendered":"\u0925\u094d\u0930\u094b\u092e\u094d\u092c\u094b\u0938\u093e\u0907\u091f\u094b\u092a\u0947\u0928\u093f\u092f\u093e \u0938\u093f\u0902\u0921\u094d\u0930\u094b\u092e (\u091f\u0940\u091f\u0940\u090f\u0938) \u0915\u0947 \u0938\u093e\u0925 \u0918\u0928\u093e\u0938\u094d\u0924\u094d\u0930\u0924\u093e"},"content":{"rendered":"

Thrombosis with thrombocytopenia syndrome<\/em> (TTS), also known as Vaccine-induced prothrombotic immune thrombocytopenia<\/em> (VIPIT) or vaccine-induced immune thrombotic thrombocytopenia<\/em> (VITT), was a rare syndrome reported in people who received adenoviral vector<\/a> COVID-19<\/a> vaccines such as Vaxzevria (AstraZeneca) and the Johnson & Johnson\/Janssen COVID-19 vaccine.<\/p>\n

Please note: adenoviral vector COVID-19 vaccines are no longer available for use in Australia. The following information remains for reference purposes.<\/strong><\/p>\n

What is TTS?<\/h2>\n

The syndrome is characterised by thrombosis formation (blood clots) combined with thrombocytopenia (low platelet count) with symptoms typically presenting in the 4-42 days after vaccination.<\/p>\n

According to the Center for Diseases Control (CDC) TTS is classified into 2 tiers based on the location of thrombosis and severity of symptoms. Cases are further classified based on if there has been recent exposure to heparin or not.<\/p>\n

Tier 1:<\/p>\n

    \n
  • uncommon site of thrombosis (eg. brain \u2013 cerebral venous sinus thrombosis [CVST] or gut \u2013 eg. splanchnic vein, associated with bowel ischaemia and surgery, portal vein or other rare venous and arterial thromboses)<\/li>\n
  • may also concurrently have thrombosis in more common locations (eg. deep vein thrombosis or pulmonary embolism)<\/li>\n
  • platelet count < 150,000 per microliter<\/li>\n
  • positive (+) anti-PF4 ELISA result is supportive, but not required for diagnosis.<\/li>\n<\/ul>\n

    Tier 2:<\/p>\n

      \n
    • common sites of thrombosis such as leg or lungs (eg. venous thromboembolism, deep vein thrombosis, pulmonary embolism)<\/li>\n
    • platelet count < 150,000 per microliter<\/li>\n
    • positive anti-PF4 ELISA result is required.<\/li>\n<\/ul>\n

      Tier 1 tends to be associated with more severe presentations and carries a higher risk of morbidity and mortality than Tier 2. Evidence suggests that Tier 1 is more common in younger age groups.<\/p>\n

       <\/p>\n