Australia: Researchers at Flinders University say they may have uncovered what causes the rare blood-clotting disorder linked to some adenovirus-based COVID-19 vaccines — a finding that could help make future vaccines safer.
The study, published in The New England Journal of Medicine, found that in very rare cases the immune system may confuse a normal blood protein called platelet factor 4 (PF4) with a similar protein linked to the adenovirus used in certain vaccines. That mistaken immune response can produce antibodies that activate platelets and lead to dangerous blood clots.
The condition, known as vaccine-induced immune thrombocytopenia and thrombosis (VITT), was reported in a small number of people during the worldwide rollout of the Oxford-AstraZeneca COVID-19 vaccine and a few other adenovirus-based shots.
Lead researcher Dr. Jing Jing Wang said the findings could help vaccine makers redesign specific components so they do not trigger the rare reaction while still providing strong protection against disease.
Independent experts welcomed the research but cautioned that any updated vaccine would still need to go through further testing to confirm its safety and effectiveness.
Health authorities have long maintained that while the clotting events were serious, they were extremely uncommon, and the overall benefits of COVID-19 vaccination in preventing severe illness, hospitalization and death far outweighed the risks.
