Blood clots

New Study into Why Astra-Zeneca Vaccine Can Cause Blood Clots

Scientists believe they have solved the mystery behind the extremely rare blood clots caused by the Oxford-AstraZeneca vaccine. MailOnline has more

A team of international experts, involving researchers from AstraZeneca, say that in a very small number of cases – about one in 100,000 in the U.K. – the vaccine can set off a chain reaction which leads to the body confusing its own blood platelets for fragments of virus.

The British-made vaccine is thought to have saved about a million lives from Covid and was the backbone of the U.K.’s initial rollout earlier in the year, helping it to become the most vaccinated country in the West.

But concerns about clots saw its restriction in under-40s in the U.K. in spring and led Pfizer and Moderna’s vaccines being favoured for young adults and as boosters. It was outright banned in many European countries and the US decided not to purchase a single dose.

The U.K. Government gave an emergency grant to a team of scientists led by Cardiff University to investigate the clotting phenomenon.

They found that the shell of the vector vaccine — the weakened cold virus used to teach cells how to neutralise Covid – sometimes acts like a magnet and attracts platelets, a protein found in the blood.

For reasons the scientists are still probing, the body then mistakes these platelets as a threat and produces antibodies to fight them. The combination of the platelets and the antibodies clumping together leads to the formation of dangerous blood clots.

But they stress this is extremely rare, with only 426 cases in the U.K. recorded the cases so far out of about 50million doses of the vaccine, equivalent to less than one in 100,000. The side effect has been linked to 73 deaths in the U.K.

Researchers are now doing further work to learn more about the process that causes these clots and if the vaccine can be tweaked to reduce this risk.

Worth reading in full.

You can read the paper in Science Advances here.

Why isn’t This Simple Step to Reduce the Risk of Blood Clots After Vaccination Not Followed?

There follows a guest post by Daily Sceptic reader Tim Cooper.

At the end of June the preprint of a paper was published, showing that accidentally injecting vaccine into a blood vessel, rather than into the muscle, could be a factor in the incidence of clotting events (VITT, etc.) associated with the AstraZeneca-type vaccines.

This concept has been mulled over in academic circles and on social media, But the issue has rather gone off the boil, possibly since these types of vaccine are not currently being widely used in developed countries (although they are still being used elsewhere).

It may be about to hot-up again though. A new paper has now been released which shows that a similar phenomenon could be associated with mRNA vaccines like Pfizer’s and Moderna’s and suggesting that faulty injection technique could be behind the adverse events.

According to Wikipedia, the purpose of intramuscular injection (as used for the Covid vaccines) “may be preferred because muscles have larger and more numerous blood vessels than subcutaneous tissue, leading to faster absorption”.

When delivering intramuscular injection, nurses are often trained to ‘aspirate’ the needle by pulling back on the plunger, with the absence of blood indicating that they haven’t hit a blood vessel. For some medicines, the product insert specifically states that “special care should be taken to prevent injection into a blood vessel”.

In general terms, though, no hard-and-fast rule exists about avoiding injection into blood vessels, because, some argue, there is no clear evidence that it matters either way – though NHS guidelines from 2006 recommended that aspiration should always be used in intramuscular injections.

Currently for Covid vaccines, U.K. health authorities do not insist on it, with Vaccines Minister Nadhim Zahawi relying on Public Health England guidance to state that: “There is no need to pull back on the plunger … because there are no large blood vessels at the recommended injection sites.” (14:08)

In America, the CDC guidelines are frankly disturbing. They appear to acknowledge the issue by stating that if you aspirate and get a flash of blood, the process should be abandoned. But then they add: “This is a waste of expensive vaccine that could be avoided by simply not aspirating.” Ah, the close-your-eyes-and-pretend-it’s-not-there approach to vaccine safety.

Man Dies from Blood Clot after Taking Moderna Covid Vaccine

Cases of blood clotting after vaccination have mainly been associated with the AstraZeneca Covid vaccine over recent months, but an American man, aged 65, has now died 12 days after his second dose of the Moderna vaccine in what is being reported as the first known death from blood clotting linked to this vaccine. The Sun has the story.

After getting the coronavirus jab, the man experienced pain in both legs, difficulty breathing and was diagnosed with thrombosis with thrombocytopenia syndrome (TTS) two days before he died.

Three days into his stay at Allegheny Health Network in Pittsburgh, Pennsylvania, the man developed cerebral venous sinus thrombosis, according to a report published on the Annals of Internal Medicine website.

This is a rare type of blood clot blocking the brain’s sinus channels of draining blood, which could lead to hemorrhages. 

Doctors searched to identify other causes behind his TTS including Covid, other viruses or thrombotic thrombocytopenia purport, a rare disorder that causes blood clots throughout the body.

The man had chronic underlying conditions including high blood pressure and hyperlipidemia, which presents itself when high levels of fat particles are in the blood.

Despite “rapid and exhaustive” treatment eliminating all other options, a solution could not be found leaving investigators believing the blood clots were caused by the vaccine.

Previously, research showed that the “rare but life-threatening” condition only occurred in individuals who received Johnson & Johnson or AstraZeneca vaccines.

Both vaccines combine genetic material taken from the coronavirus and genes of the adenovirus, producing an immune response.

The findings show that the side effects can also occur when someone gets a vaccine that has messenger RNA (mRNA).

Because blood clots do occur after vaccinations, the report claims, “it should not dissuade people from getting the Covid jab”.

Earlier this month, the U.S. Food and Drug Administration announced that it would add a warning to the Moderna vaccine – as well as the Pfizer vaccine – after the Centers for Disease Control and Prevention said there is a “likely link” between them and cases of heart inflammation, particularly in children and young adults.

The Sun report is worth reading in full.

Under-40s to be Offered Alternative to AstraZeneca Jab

The Joint Committee on Vaccination and Immunisation (JCVI) has issued new guidance today saying that adults aged 30 to 39 without underlying health conditions should be offered an alternative to the Oxford-AstraZeneca vaccine. MailOnline has more.

Britons under 40 should be offered an alternative to the Oxford/AstraZeneca Covid vaccine due to its link to rare blood clots, health officials announced today.

Advisers made the recommendation after more adults suffered the potentially-fatal clotting disorder in the past week.

They said the absolute risk of the clots is still “extremely small”, affecting around one in 100,000 people given the British-made jab.

So far regulators have spotted major blood clots in 242 people, of whom 49 died. But they are occurring more in younger adults, with a rate of around one in 60,000 under-40s.

Experts said the infection rate in the UK is now so low that the risk of the rare clots outweigh that of Covid in younger adults, who often only suffer mild illness. They will be offered the Pfizer or Moderna vaccines instead.

That final point is interesting. Does it mean that health officials have calculated that the risk of dying from a blood clot after being receiving the AZ jab is greater than the risk of someone under-40 with no underlying health conditions dying from Covid? To date, 49 people have died from blood clots after being given the AZ vaccine. If we assume that at least a half of the 35 million Britons who’ve been inoculated got an AZ jab (a conservative assumption), that means the risk of dying from a blood clot after receiving the AZ vaccine is ~49/17,500,000.

So is the JCVI saying that the risk of someone under-40 with no underlying health conditions dying from COVID-19 is < 49/17,500,000?

Even I hadn’t realised the risk was quite so infinitesimally small.

Worth reading in full.

AstraZeneca No Worse Than Other Vaccines for Blood Clots, Study Finds

A new pre-print from a team at the University of Oxford has found that the AstraZeneca vaccine, which is being restricted or banned around the world over links to blood clots, does not appear to cause the rare side effect at a much greater rate than the Pfizer or Moderna vaccines. However, on the basis of current reporting rates, the same complications are many times more likely to be caused by the disease itself, they say. The Independent has the story.

The risk of developing a rare brain clot from COVID-19 is about eight times greater than from the AstraZenecaOxford vaccine, according to a new study.

Researchers at the University of Oxford, who are not linked to the vaccine, also found that people infected with coronavirus are “manyfold times” more likely than normal to develop the rare clotting disorder, known as cerebral venous thrombosis (CVT), where blood clots in the veins that run from the brain.

“There’s no doubt that Covid is a much greater risk of this [condition] than any of the vaccines,” said Professor Paul Harrison, a co-author of the study.

The research, which has yet to be peer-reviewed, drew comparisons between more than 500,000 COVID-19 patients in the US and 34 million people in Europe who have received the AstraZeneca vaccine, as well as the background level of CVT in the general population.

For COVID-19, the incidence rate of CVT stands at 39 cases per one million people, the study showed. But for a million people vaccinated with the AstraZeneca jab, there will be just five cases of CVT over a two-week period. …

The study also suggested that four cases of CVT are likely to occur in one million people vaccinated with either the Moderna or Pfizer/BioNTech jab. However, the scientists warned that the data on this is too thin to establish any firm conclusions.

The researchers acknowledge a number of limitations in their research.

The scientists warned that all comparisons must be interpreted cautiously since data are still accruing and drawn from different sources. They added that their research was unable to determine the relative risk of developing CVT after vaccination due to uncertainty around the baseline rate for this condition.

Nor did the study address the incidence rate of thrombocytopenia in COVID-19 patients and people who had been vaccinated. This condition, where a patient presents abnormally low levels of platelets, has been detected alongside CVT in the cases of concern reported to date. …

The Oxford researchers drew their COVID-19 patient data from a US-based electronic health records network which had recently been used by the team to show the neurological and psychiatric consequences of coronavirus.

This database, which is made up of a total of 81 million US patients, provided clear detail on CVT cases that had been detected among people infected with coronavirus, the experts said – though they acknowledged there may be under-reporting of the condition in medical records.

As for the incidence rate of CVT among people vaccinated with the AstraZeneca jab, this was taken from the European Medicines Agency’s database, which covered more than 34 million individuals at the time of publication.

A further observation is that the COVID-19 patients in the study are drawn from a “federated electronic health records network recording anonymised data from healthcare organisations, primarily in the USA”. This suggests they are hospital patients, or at least those who have sought medical assistance, and so are not representative of all Covid infections but only the more serious. This contrasts to the vaccinated group, which is the healthy population as a whole, albeit with more vulnerable groups often vaccinated first. This may skew the comparison considerably, making blood clots among those infected with Covid appear much more common than they are.

How will regulators respond, having restricted one vaccine over this issue (and increasingly the Johnson & Johnson one as well), will they not have to be consistent? Will they remove the restrictions from AZ and J&J, or apply them equally to the other two, or somehow justify the discrepancy? Will be interesting to watch this play out.