Scientific teams from Germany and Norway found that people who developed the clots after vaccination had produced antibodies that activated their platelets, a blood component involved in clotting. The new reports, published by New England Journal of Medicine, add extensive details to what the researchers have already stated publicly about the blood disorder. Younger people appear more susceptible than older ones, but researchers say no pre-existing health conditions are known to predispose people to the rare reaction. That is worrisome, they say, because there is no way to tell who is at high risk.
During a briefing on Friday, Dr. Andreas Greinacher, an author of the German report, said it was a “likely possibility” that the people who developed the clotting disorder had some rare, unknown biological traits — what he called “individual co-factors” — that predisposed their immune systems to make powerful, misdirected antibodies in response to the vaccine. He called that “good news” for the general population, who do not have the co-factors. But, he added: “We have no way to predict who will develop these antibodies.”
He called the deaths in young people “tragic,” but noted that the numbers were small. “Not vaccinating will bring many, many more people with severe complications than vaccination,” Greinacher warned. Six of the 11 people part of the study, including nine women ages 22 to 49, died. Nine had cerebral venous thrombosis, a clot blocking a vein that drains blood from the brain. Although most of the patients were female, it is not known whether they are more vulnerable. The article described specialised blood tests that can be used to diagnose the disorder, and distinguish it from other, more common clotting problems. The researchers suggested treatment with a blood product called intravenous immune globulin, which is used to treat various immune disorders.
The second report, from Norway, described five patients, one male and four female health workers ages 32 to 54, who had clots and bleeding from seven to 10 days after the Astra jab. Four had severe clots in the brain, and three died. Severe headaches were among early symptoms. Like the German patients, all had high levels of antibodies that could activate platelets. The Norway team also recommended treatment with intravenous immune globulin. The researchers said the disorder was rare, but “a new phenomenon with devastating effects for otherwise healthy young adults.” In a statement, AstraZeneca has said it is working to understand the “individual cases, epidemiology and possible mechanisms that could explain these extremely rare events.” NYT