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 AstraZeneca Acknowledges Covishield Vaccine’s Potential Side Effects


AstraZeneca, the manufacturer of the Covishield vaccine for the Covid-19 pandemic, has admitted that the inoculation carries potential side effects. This admission was made in a legal document presented before the High Court of Justice in London. The document conveys that the Covid vaccine can, in extremely rare cases, induce Thrombosis with Thrombocytopenia Syndrome (TTS).


GS II: Health

Dimensions of the Article:

  1. AstraZeneca’s Position on Thrombosis with Thrombocytopenia Syndrome (TTS)
  2. Covishield: An Overview
  3. Thrombosis with Thrombocytopenia Syndrome (TTS)

AstraZeneca’s Position on Thrombosis with Thrombocytopenia Syndrome (TTS)

  • AstraZeneca’s statements regarding Thrombosis with Thrombocytopenia Syndrome (TTS) were made in court documents filed in the United Kingdom in response to a lawsuit against the company. Here’s a summary of their remarks:
    • AstraZeneca is facing legal action over health claims related to the vaccine it developed with the University of Oxford during the Covid-19 pandemic in 2020.
    • In the court documents, AstraZeneca denied that TTS is caused by the vaccine on a broad scale.
    • However, the company acknowledged the possibility of TTS occurring as a result of its vaccination, albeit in “very rare cases.”

Covishield: An Overview

Development and Production

  • Developed by AstraZeneca in collaboration with the University of Oxford.
  • In India, marketed under the brand name Covishield, manufactured by the Serum Institute of India (SII) in Pune.

Administration in India

  • Vaccination commenced in India on January 16, 2021.
  • Notable observations:
    • Indian government issued a caution regarding its administration in individuals with thrombocytopenia.
    • Thromboembolic events reported at a rate of 0.61 cases per million doses.
    • Covishield continues to have a positive benefit-risk profile according to the Union Health Ministry.

International Concerns and WHO Observations

  • European countries temporarily paused the use of AstraZeneca vaccine due to reported cases of blood clotting.
  • World Health Organization (WHO) noted cases of Thrombosis with Thrombocytopenia Syndrome (TTS) post-Covishield vaccinations.
  • WHO stated that while TTS risk with Covishield vaccines appears low based on available data.

Thrombosis with Thrombocytopenia Syndrome (TTS)

Definition and Characteristics

  • Rare condition characterized by blood clot formation (thrombosis) and low platelet counts (thrombocytopenia).
  • Associated with certain COVID-19 vaccines, particularly those using adenovirus vectors like Covishield.
    • Adenovirus vectors are non-enveloped, double-stranded DNA Virus that are commonly used for gene therapy, vaccination, and cancer gene therapy. 
    • They are considered the most efficient gene delivery vehicles due to their safety profile and expression.

Mechanism and Hypotheses

  • Mechanism not fully understood but hypothesized to involve vaccine-triggered immune response leading to platelet activation and clot formation.
  • Resembles autoimmune heparin-induced thrombocytopenia, involving heparin-triggered immune response.

Symptoms and Complications

  • Symptoms include breathlessness, chest or limb pain, skin bruising beyond the injection site, headaches, numbness, etc.
  • Complications depend on clot location, including stroke, heart attack, and respiratory issues.

Risk Factors

  • Factors predisposing individuals to TTS include age, gender (more common in younger women), and potentially genetic factors.

-Source: Indian Express, The Hindu

May 2024