In recent weeks, the United States and several European countries including Norway and Denmark have either temporarily stopped or stopped launching these vaccines.
Eric Van Gorb, a professor at Erasmus University in the Netherlands, told the newspaper Wall Street Journal: “Understanding the reason is most important for the next generation of vaccines, because the Corona virus will remain with us and vaccination is likely to become seasonal.”
Andreas Grenacher, a blood expert and his team at the University of Greifswald in Germany, believes that the so-called virus vector vaccines such as AstraZincia and Johnson, which use weak live viruses such as the cold-causing virus or adenovirus to transfer the genetic material of the Corona virus to human cells to form immunity against the virus, which it fights if it infects a person, It can cause autoimmunity that leads to blood clots.
Grenacher attributed this to the presence of a link between the distant proteins in the body affected by clots and some preservatives in the vaccine.
The German team examined more than 1,000 proteins in the AstraZeneca vaccine, in addition to a preservative known as “ethylene diamine tetraacetic acid” or “EDTA”, which is a common substance in drugs and other products, that helps these proteins spread into the bloodstream, and it is the one that interacts with Platelets, or PF4, form compounds that stimulate antibody production.
Some of the side effects caused by vaccines, along with PF4 compounds, can trick the immune system into believing that the body has been infected with the bacteria, which leads to the release of antibodies that spiral out of control and cause clotting and bleeding.
Professor John Kelton of McMaster University in Canada, whose group runs a reference laboratory in Canada to screen patients with symptoms of blood clotting after vaccination, said the laboratory had repeated some of Professor Greenacher’s research and confirmed his findings.
The type of clot caused by the vaccine is known as immune thrombocytopenia, or “VITT”.
Some scientists also believe that adenoviruses themselves could play a role in triggering the condition because they are linked to blood clotting. Others speculate that the affected people could have a genetic predisposition, or that their immune systems had previously developed the problematic antibody.
While Van Gorb has suggested, another theory is that the short but strong flu-like symptoms reported by many recipients after an injection also cause inflammation that can trigger or worsen autoimmune reactions leading to blood clots.
Thrombosis occurs between 1 in 28,000 to 100,000, according to European data, and is extremely rare among the hundreds of millions of doses administered so far. Most people who have had these clots recover, but between a fifth and a third will die, and others may suffer permanent consequences.
Data from US and European regulators so far indicates that girls are mainly affected by this condition. But many scientists, including Sabine Ischinger, an Austrian hematologist, do not believe this. He said there was no indication that taking the contraceptive pill or having a history of similar illnesses would put the vaccine recipient at a greater risk.
Professor Grenacher said: “Corona virus is much more dangerous than this extremely rare case.”