An international team of scientists has completed a multi-year study explaining why the Oxford/AstraZeneca and Johnson & Johnson vaccines caused a rare side effect—blood clotting (thrombosis)—in some patients. This discovery will assist vaccine manufacturers in developing even safer preparations in the future.
These vaccines utilize a so-called ‘adenoviral vector’—a harmless virus that carries necessary information into the body. The study revealed that the immune systems of some individuals fail to distinguish this harmless virus from a natural protein in the body (PF4). Consequently, the body begins to fight its own protein, leading to a sharp drop in blood platelets and the formation of clots.
Scientists have pinpointed the exact part of the virus responsible for this ‘glitch.’ According to them, modifying or removing this specific protein in future vaccines will entirely eliminate this rare but dangerous side effect.
As it turns out, adenoviral technology, which is highly effective against various diseases, will continue to be used safely. The researchers clearly demonstrated that the rare reaction was caused not by any vaccine additive, but by the viral vector itself. Experts evaluate this case as a prime example of the effective collaboration between science and regulatory bodies.
