Finally, scientists explain why the AstraZeneca vax causes TTS

Researchers believe they’ve hit on the mechanism that triggers the rare clotting syndrome

Scientists believe they now understand why AstraZeneca’s COVID-19 vaccine causes rare blood clots, raising the prospect of tweaking the shot to negate the risk.

Blood clot

A new study in Science Advances suggests the chimpanzee adenovirus vector used in the vaccine can act like a magnet for platelet factor 4 (PF4) proteins circulating in the blood.

The UK and US researchers say the resulting vector-PF4 complex can trigger an autoimmune reaction that ultimately leads to the rare thrombosis with thrombocytopenia