Today, the AstraZeneca coronavirus vaccine is associated with another rare bleeding disorder.
Researchers say about one in 100,000 people affected will suffer from idiopathic thrombocytopenic purpura (ITP).
The condition can cause slight bruising on the body and can leave some with a rash with purple spots.
Nearly 350 Britons have been struck by a separate, rare clotting disorder since receiving the AstraZeneca vaccine, developed by Oxford University.
The complexity – blood clots that appear along with abnormally low levels of platelets, cells that cause blockages – deceived health managers to advise under the age of 40 get a different stroke.
ITP can cause slight bruising on the body and can leave some with a rash with purple spots called petechiae (pictured)
Experts from the University of Edinburgh, who revealed the connection with the ITP, did not say how many people also continued to develop clots.
But they said it was likely to be a “manifestation” of the underlying complication.
Researchers noticed the connection after analyzing data from 5.4 million people in Scotland between December 8 and April 14. At that time, 1.7 million received their first dose of the Oxford stroke, while 800,000 had the Pfizer-BioNTech vaccine.
They examined the health records of vaccinated individuals to identify any previous ITP problems, clotting or bleeding disorders, and compared them to people who had not been vaccinated.
There are no cases related to Pfizer’s Covid, which works in a completely different way.
They said the finding of the blow – which has been used 24 million times in Britain – is “reassuring”.
What is idiopathic thrombocytopenic purpura (ITP)?
ITP is a condition that causes the immune system to destroy platelets.
Platelets are blood cells that clot the blood and are needed to prevent bleeding and bruising after injury.
People can get ITP after a virus, vaccine or certain medications, but the cause is often unknown. It is usually diagnosed with a blood test.
Between 3,000 and 4,000 people in the UK have ITP.
Someone who does not have enough platelets may bruise very easily or may not be able to stop the bleeding when cut.
Other common symptoms include petechiae – a rash of bloodstains that may appear red, purple or brown – bruising and nosebleeds.
The normal platelet count is between 100 and 400 thousand million per liter of blood.
Those who have ITP are unlikely to experience symptoms of bleeding unless their platelet count is below 20,000 million per liter of blood.
ITP in children almost always improves without treatment.
But adults are usually prescribed a short course of steroids to treat the condition.
For AstraZeneca prick, the risk of developing ITP continued for almost four weeks after prick.
There is no evidence that the AstraZeneca stroke caused blood clots despite growing claims and this is still being investigated.
Experts also insist that the benefits of the stroke outweigh the risks for most adults.
British health leaders, advised only under the age of 40, received a different vaccine because of their low risk of becoming seriously ill, along with the very low prevalence of Covid at the time.
The JCVI recommendation, which advises No. 10, may change if cases get out of hand due to the Indian version.
Edinburgh researchers said that the risk of ITP after the breakthrough of AstraZeneca – estimated at 11 per 1 million doses – was similar to the percentage observed for the MMR vaccine.
Professor Aziz Sheikh, the study’s author, argues that the “very low risk” of ITP, clotting and bleeding should be “seen in the context of the very clear benefits” of a stroke that has been shown to save lives many times.
Dr Will Lester, a consultant hematologist at the University Hospital Birmingham NHS Foundation Trust, who was not involved in the study, said ITPs were often “manageable” and the risk of death from the condition was “very rare”.
He insisted that “there is currently no evidence” that any vaccine against Covid is more risky than another.
Patients who developed ITP had a mean age of 69 years and often had at least one underlying health condition, such as heart disease or diabetes.
The first clots to worry about people receiving the AstraZeneca vaccine were those that appeared in the veins near the brains of younger adults in a condition called CSVT (cerebral sinus venous thrombosis).
Since then, however, humans have developed clots in other parts of their bodies.
All clots occur with thrombocytopenia, an abnormally low platelet count – an unusual effect because platelets are usually used by the immune system to build clots.
In most cases, people recover completely and blockages are usually easy to treat if they are noticed early, but they can cause strokes or heart or lung problems if they go unnoticed.
Symptoms depend entirely on where the clot is, and brain blockages cause excruciating headaches. Clots in the main arteries of the abdomen can cause constant pain in the stomach, and those in the legs – swelling of the limbs.
Some countries have decided to stop using the device altogether, with Denmark and Norway choosing not to release it. Other countries have limited it to certain age groups.
The Oxford vaccine was approved in the UK in December and is recommended for use for over 40 years
But the AstraZeneca stroke is not the only one thought to cause blood clots. The Johnson & Johnson single-dose vaccine, which has not yet been approved in the UK, has been linked to 28 cases in the United States of more than 10.4 million shots.
Researchers in Germany believe that the problem lies in the adenoviral vector, a common cold virus used so that both vaccines can enter the body.
Academics investigating the problem say the complication is “completely absent” in mRNA vaccines such as Pfizer and Moderna, as they have a different delivery mechanism.
Experts from Goethe University in Frankfurt and the University of Ulm in Helmholtz say that the AstraZeneca vaccine enters the cell nucleus – a patch of DNA in the middle. By comparison, the Pfizer jab enters the fluid around it, which acts as a protein factory.
Pieces of coronavirus protein that get inside the nucleus can break down and the unusual fragments can then be thrown into the bloodstream, where they can cause a small number of people to clot, scientists say.
The JCVI recommends that a vaccine other than Oxford be given at the age of 39, due to concerns about the very low risk of possible blood clots. Data show that more than 40 million people received their first stroke in the UK, while more than 28 million received their second stroke