Some COVID-19 vaccines have been linked to harmful however extremely uncommon blood clots. Now a small research is revealing new particulars on how these clots type.
Vaccine-induced antibodies connect to a protein concerned in blood clotting at an identical spot that the anticoagulant drug heparin does, spurring platelets to type clots, researchers report July 7 in Nature.
Researchers already knew that COVID-19 vaccines developed by Johnson & Johnson and AstraZeneca can generally trigger the physique to make antibodies that connect to a protein known as platelet issue 4, or PF4, which then causes platelets to type clots (SN: 4/13/21; SN: 4/7/21; SN: 4/16/21). The vaccine-induced situation is much like what occurs with heparin, a blood thinner that may additionally connect to PF4. When heparin binds to the protein, some folks’s immune programs then assault the certain molecules, a counterintuitive situation known as heparin-induced thrombocytopenia additionally characterised by clotting.
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Even in mild of these similarities, it was nonetheless unclear whether or not antibodies sparked by heparin therapy or COVID-19 vaccines used the identical mechanism to immediate platelets to clot.
Angela Huynh, a platelet immunologist at McMaster College in Hamilton, Canada, and colleagues analyzed PF4-recognizing antibodies from 10 heparin-induced thrombocytopenia sufferers and 5 sufferers with COVID-19 vaccine–induced clots, a situation known as vaccine-induced immune thrombotic thrombocytopenia, or VITT. The immune proteins from VITT sufferers hooked up to an identical spot on PF4 as heparin does, hinting that heparin and COVID-19 vaccines trigger blood to clot in comparable methods.
PF4-binding antibodies won’t be the entire story in relation to clotting, the researchers say. Figuring out how the clots type might assist in treating them.
Public well being officers proceed to say that the vaccines’ advantages towards COVID-19 far outweigh the dangers of the uncommon clotting situation (SN: 4/23/21).
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