TTS SYNDROME (Syllabus GS Paper 3 – Sci and Tech)

News-CRUX-10     1st May 2024        
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Context: Global pharmaceutical giant AstraZeneca has said that its AZD1222 vaccine against Covid-19, which was made under licence in India as Covishield, could cause low platelet counts and formation of blood clots in “very rare” cases.

Thrombosis with Thrombocytopenia Syndrome (TTS)

  • About: TTS is characterized by blood clots (thrombosis) combined with low levels of platelets (thrombocytopenia), which are necessary for blood clotting. 

o It often involves unusual blood clot locations, such as in the brain (cerebral venous sinus thrombosis) or abdomen.

  • Symptoms of TTSSevere or persistent headaches, blurred vision, Shortness of breath, Chest pain, Leg swelling, Persistent abdominal pain and Easy bruising or tiny blood spots under the skin beyond the injection site.
  • Age Factor: TTS risk slightly higher in individuals under 60.
  • Variety of Blood Clot Locations:

o Blood clots associated with AstraZeneca vaccine can manifest in multiple areas:

o Brain (CVST)

o Abdomen (Splanchnic vein thrombosis)

o Lungs (Pulmonary embolism)

o Limb veins (DVT)

o Arteries (Arterial thrombosis)

Were incidents of blood clots reported in India as well?

  • Incidents of Blood Clots in India: The Indian government reported 26 potential thromboembolic events related to Covishield in May 2021.
  • Occurrence Rate: With over millions of doses administered, the rate of potential thromboembolic events for Covishield was 0.61 cases per million doses, or 0.000061%.
  • Government Assessment: The Union Health Ministry labeled the risk as "minuscule," emphasizing Covishield's positive benefit-risk profile and its potential in combating Covid-19.
  • Covaxin's Status: No potential thromboembolic events were reported for Covaxin, Bharat Biotech's indigenous vaccine.
  • Ethnic Risk Variation: The Ministry highlighted scientific literature indicating a 70% lower risk of blood clotting in individuals of South and Southeast Asian descent compared to those of European descent.