Misleading Claims on Well-Known Rare Risk of AstraZeneca COVID-19 Vaccine
SciCheck Digest
A rare risk of dangerous blood clots associated with the AstraZeneca COVID-19 vaccine was identified and reported in early 2021. This month, the company announced it was pulling the vaccine off the market globally, citing a decline in demand. Social media posts misleadingly linked the decision to the company having “admitted” the rare side effect “for the first time” in court documents and used it to impugn all vaccines.
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The association between the AstraZeneca COVID-19 vaccine and a rare and dangerous blood clotting condition combined with low blood platelets has been known for more than three years. The condition is known as thrombosis with thrombocytopenia syndrome, or TTS, in general, and vaccine-induced thrombotic thrombocytopenia, or VITT, when it implies an association to vaccines.
The European Medicines Agency, which regulates vaccines in the European Union, first warned of the possible link between the vaccine and “very rare cases of blood clots associated with thrombocytopenia, i.e. low levels of blood platelets” on March 18, 2021. In a statement issued that same day, the pharmaceutical company acknowledged the finding and said it “recognises and will implement” EMA’s recommendations, including updating the product information to warn about the reported cases.
A few weeks later, in April 2021, the EMA the unusual blood clots “should be listed as very rare side effects” of the vaccine. TTS is included in the “possible side effects” section for users for (page 30), one of the brand names of the vaccine along with . TTS has also been listed in Covishield’s under the “special warnings” section, as a side effect in the since at least August 2021, and as a possible adverse reaction in an from its manufacturer that was updated on July 5, 2021.
