Blood clots from AstraZeneca Covid vaccine are easy to treat, say Canadian doctors.

14 June 2021 By Paul Martin

There’s an easy and efficient way, say scientists, to treat the extremely rare cases of serious blood-clots that develop from AstraZeneca’s vaccine against Covid.

Three patients in Canada developed what is called “vaccine-induced immune thrombotic thrombocytopenia”, or VITT, after receiving the AstraZeneca vaccine.

That produces blood clots — a symptom that led to panic across Europe in particular. It even led to countries that desperately needed AstraZeneca vaccine, which can be stored at near-normal temperatures, to decline shipments or even throw away what they had received.

Most experts strongly rejected any slow-down or stop to the AstraZeneca rollout, arguing that the risk of a fatal blood-clot was tiny compared to the risk of not taking a vaccine.

In the Canadian cases, two of the three patients developed blood clots in their legs, and the third had blood clots blocking arteries and veins inside the brain.

The patients recovered after receiving treatment that combined anti-clotting drugs and high doses of intravenous immunoglobulin.

The study was published this week in the New England Journal of Medicine.

“We can diagnose it accurately with our tests, treat it and we know exactly how the treatment works,” said study author Ishac Nazy, scientific director of the McMaster Platelet Immunology Laboratory.

VITT occurs when antibodies attack a blood protein called platelet factor 4, or PF4. This activates platelets in the blood, causing them to clump together and form clots, the study authors explained.

Blood samples taken from the three patients after treatment showed reduced antibody-mediated platelet activation in all of them.

“We now understand the mechanism that leads to platelet activation and clotting,” Nazy said.