Covishield’s Rare Side Effect: A Closer Look at Thrombosis Thrombocytopenia Syndrome (TTS) Incidence


New Delhi: A recent analysis reveals that a minuscule fraction of individuals—approximately seven to eight out of every million—administered with the Covishield coronavirus vaccine may encounter a rare but serious condition known as thrombosis thrombocytopenia syndrome (TTS). Dr. Raman Gangakhedkar, India’s esteemed epidemiologist and former ICMR scientist, reassures that the risk associated with Covishield is negligible.

Dr. Gangakhedkar elaborates that the likelihood of experiencing TTS is marginally higher post the initial vaccine dose, decreasing subsequently with the second and third doses. Notably, any potential side effects typically manifest within the first few months following vaccination.

In a candid admission, AstraZeneca, the pharmaceutical behemoth, has recognized the possibility of TTS as a rare complication of its COVID-19 vaccine, AZ Vaxzevria, also manufactured by the Serum Institute of India under the name Covishield. This vaccine has been administered to over 90% of India’s population.

The recognition of TTS as a rare adverse effect emerged within half a year following Covishield’s rollout. Dr. Gangakhedkar points out that this discovery does not alter the existing understanding of the vaccine’s safety profile.

Emphasizing the rarity of the risk, Dr. Gangakhedkar compares it to everyday hazards such as road accidents or adverse reactions to common medications. He advocates for a balanced perspective, considering the vaccine’s overwhelmingly positive impact on public health.


The Daily Telegraph has reported that AstraZeneca, in a legal document for a court case involving 51 claimants, conceded that TTS could occur in “very rare cases” as a result of vaccination.

Dr. Gangakhedkar underscores the importance of risk versus benefit analysis in emergency vaccine approvals, asserting that the benefits of Covishield far outweigh the risks. His approach simplifies complex medical information, making it accessible and understandable to the public. The expert’s stance is clear: the minimal risk of TTS should be weighed against the vaccine’s significant role in saving lives during the pandemic.