Tom Gordon, head of immunology at Flinders University in South Australia, whose investigative work led to the discovery, said that the extent of susceptibility to this complication remains unknown. He described the immune reaction associated with the vaccine as "a new disease" stressing on the likelihood of more cases being documented as hematologists and intensive care specialists become more used to these conditions.
According to the Yale School of Medicine, out of over 18 million recipients of the single-dose J&J vaccine, there were 60 reported cases of the clotting disorder, resulting in nine deaths.
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Following a small number of clot-related deaths associated with the AstraZeneca vaccine, it was withdrawn or restricted in Denmark, Norway, and other nations in 2021. In Australia, where the AstraZeneca shot has not been available since March 2023, the complication occurred in approximately 2-3 people per 100,000 vaccinated individuals under the age of 60. The European Commission revoked the marketing authorisation for this vaccine in March 2024.
“AstraZeneca welcomes any further examination of the possible underlying mechanism of thrombosis with thrombocytopenia syndrome (TTS), given that, despite extensive investigation, we do not yet understand the mechanism that can in very rare cases be a trigger for TTS,” a spokesperson for the company told Bloomberg.
J&J also said that it is open to research that helps in the development of safe and effective vaccines.
“More data are needed to fully understand potential factors that may be associated with this rare event, including its potential relationship with adeno- and other viruses, to draw appropriate conclusions about the underlying pathogenesis,” the company said in an email sent to Bloomberg.
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Upsides of the vaccine
Both vaccines were crucial in vaccine campaigns in the initial phases of the pandemic. An assessment indicated that the AstraZeneca vaccine potentially saved around 6.3 million lives in 2021. However, the mRNA vaccines produced by Pfizer Inc.-BioNTech SE and Moderna Inc. were subsequently discovered to offer higher effectiveness against Covid and have been modified to address more recent virus variants.
(With inputs from agencies)
