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

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 TTS:  Severe 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.