Frantic race to understand thrombosis caused by Covid vaccines – economic, financial and business news

The rare blood clotting reaction caused by the Oxford / AstraZeneca and Johnson & Johnson coronavirus vaccines have been investigated lively scientific debate why the injection can trigger this response and how to stop it.

The reaction, which some scientists have called vaccine-induced immune thrombotic thrombocytopenia (VIITT, por sus siglas en ingls), se ha registrado en 300 de las 33.6 million de personas que han recibido la vacuna de AstraZeneca en Europa y en al menos 8 de los 7.4 million receptores de la inyeccin de J&J in the USA.

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As an answer, AstraZeneca vaccine use has been restricted or discontinued in more than a dozen countriesIn the United States, inoculation with doses of J&J has been halted and the company has postponed its launch in the EU.

Scientists claim that if they are successful identify the mechanism By pairing vaccines with this extremely rare and often fatal disease, drug makers will be able to tailor their formulas so that this doesn’t quite happen.

“When you know the mechanism, you know how to prevent it”said Johannes Oldenburg, professor of transfusion medicine at the University of Bonn, who chairs a team investigating the problem and possible treatments.

But for now, the scientific community is divided, because some believe the response could be caused by the adenoviral vector of both vaccines, and others, including scientists at the University of Oxford who worked on the AstraZenca vaccine, argue that there is no evidence to confirm it.

A group of laboratory scientists from Germany and Austria, led by coagulation expert Andreas Greinacher, noted in March that the unusual constellation of symptoms looks like a rare reaction to heparin, a blood thinning drug called heparin-induced thrombocytopenia (TIH).

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HIT occurs in four out of every million people who receive the drug and causes the body to produce antibodies to a protein called platelet factor 4 (PF4). This causes huge clots to form in the blood in unexpected places, such as the brain and abdomen, which deplete the body’s meager supply of platelets.

AstraZeneca and J&J vaccines are vaccines with adenoviral vectors, like the Russian Sputnik V and the one developed by the Chinese company CanSino Biologics, which means that They use an adenovirus, like the common cold, to introduce the vaccine protein into the body.

the four vaccines use a slightly different adenovirusBut in each case, scientists are removing the genetic material that will allow it to spread or cause disease. This material is then replaced with genetic instructions to replicate the spicular protein on the surface of the Sars-Cov-2 virus and make the body believe it has been infected with Covid-19.

Currently, one of the main hypotheses among scientists is that it is in fact the adenoviruses of the two different vaccines that elicit an exaggerated immune response in a very small number of people, generating antibodies that attack the PF4 blood platelets.

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Hildegund Ertl, a researcher working with adenovirus vaccines at the Wistar Institute in Philadelphia, said the reaction of the J&J and AstraZeneca vaccines appears to be very similar, so “There is concern that the cause is adenovirus.”

AstraZeneca informs you that make an effort “to understand individual cases, the epidemiology and possible mechanisms that could explain these extremely rare events. ”

Sue Pavord, who chairs the UK Hematology Expert Panel, noted that the chimpanzee adenovirus used in the AstraZeneca vaccine does not typically infect humans, but said some of the vaccine’s genetic material could trigger this response. rare immune system. through a process known as “Sequence homolog”.

There may be, he added, a genetic link between heparin and the DNA or protein sequences contained in the adenovirus, causing an almost identical antibody response in some patients. “It looks a lot like HIT without heparin. It’s the same mechanism.”, He said.

Pavord and other scientists are also working to find treatments for people with VIITT, which has so far caused the death of one in five people who have developed symptoms in the UK.

The most effective are regular infusions of something called gamma globulin – a protein fraction of blood plasma that contains useful antibodies – and has already halves the death rate.

John Bell, a senior professor of medicine at the University of Oxford who oversaw joint vaccine work between the university and AstraZeneca, argued, however, that the HIT hypothesis lacked strong evidence.

They tried to compare this syndrome to an HIT, “but no one has been able to explain exactly how it works “Bell said. “I think the answer is nobody knows, including hematologists.”

Oxford scientists analyzed the blood serum of 500 people who took part in their vaccine trials and found that none of them contained PF4 antibodies, according to people close to the research.

Rather than a reaction to the adenoviral vector, Bell believes the blood disorder is more likely to be a response to the vaccine spike protein.

Supporters of this hypothesis point out that Sars-Cov-2 causes more serious, and much more frequent, clotting problems than any of the current Covid-19 vaccines. Oxford researchers recently discovered that blood clots occur in 39 of 1 million coronavirus patients.

“It’s a hallmark of the disease, which means it’s induced by the virus, or a little bit of the virus,” Bell said. “Some vaccines can produce more spike protein than others. I think that’s something we need to consider.”

Adenoviral vector vaccines have been in development since the 1980s and they’ve been proven, but until Covid-19, the technology had only been used in a commercially available inoculation: a rabies vaccine to immunize wild animals.

Other scientists also believe it’s too early to blame the adenoviral vectorespecially since a definitive causal relationship between the blood disorder and any of the vaccines has not yet been established.

“It could be a contaminant, or the preservatives, or the stabilizers.”said Gary Nabel, who discovered the first roll-on vaccine and was the scientific director of Sanofi until the end of last year. “If it was one of them, it could be wiped out and returned [que la vacuna] is potentially safe. “

Traduccin: Mariana Oriolo