AstraZeneca’s coronavirus vaccine has been linked to another rare bleeding disorder today.
Researchers say that about 1 in 100,000 people who receive the vaccination will have idiopathic thrombocytopenic purpura (ITP).
The condition can cause easy bruising around the body and can leave a purple rash behind.
Nearly 350 Brits were infected with a separate rare coagulation disorder after receiving the AstraZeneca vaccine developed by Oxford University.
The complication – blood clots that appear alongside abnormally low platelet levels, cells that cause blockages – has led health professionals to give under-40s a different prick.
ITP can bruise easily around the body and leave some with a purple dotted rash called the petechiae (pictured).
University of Edinburgh experts who uncovered the link to ITP did not say how many people also developed blood clots.
But they said it was likely a “manifestation” of the main worrying complication.
The researchers discovered the link after analyzing data from 5.4 million people in Scotland between December 8 and April 14. By then, 1.7 million had received their first dose of the Oxford vaccine, while 800,000 had the Pfizer BioNTech vaccine.
They examined the vaccinated people’s health records to identify previous problems with ITP, coagulation or bleeding disorders and compared these with people who had not been vaccinated.
No cases have been linked to Pfizer’s Covid jab, which works in an entirely different way.
They said the finding for this sting – which was administered 24.6 million times in the UK – was “comforting”.
What is idiopathic thrombocytopenic purpura (ITP)?
ITP is a disease that causes the immune system to destroy platelets.
Platelets are blood cells that clot the blood and are used 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’s 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 can bruise very easily or cannot stop bleeding if they are cut.
Other common symptoms include petechiae – a pinprick-like rash made from blood spots that may appear red, purple, or brown – bruising and nosebleeds.
A normal platelet count is between 100 and 400 billion per liter of blood.
Those with ITP are unlikely to experience bleeding symptoms unless their platelet count is below 20 billion per liter of blood.
ITP in children almost always gets better without treatment.
However, adults are usually prescribed a short steroid cycle to manage the condition.
With the AstraZeneca vaccination, the risk of developing ITP was almost four weeks after vaccination.
There’s no evidence that the AstraZeneca’s sting caused blood clots, despite rising claims, and this is still being investigated.
The experts also insist that the benefits of vaccination outweigh the risks for the vast majority of adults.
The British health chiefs only advised under 40-year-olds to receive a different vaccine due to their low risk of getting seriously ill, in connection with the then very low prevalence of Covid.
The JCVI’s recommendation advising No. 10 may change if cases get out of hand due to the Indian variant.
Edinburgh scientists said the risk of ITP after vaccinating AstraZeneca – calculated at 11 per 1 million doses – is similar to that of the MMR vaccine.
Professor Aziz Sheikh, study author, claimed that the “very low risk” of ITP, clotting and bleeding must be seen “in the context of the very clear benefits” of vaccination, which has been repeatedly shown to save lives.
Dr. Will Lester, a consultant hematologist at the University Hospitals Birmingham NHS Foundation Trust who was not involved in the study, said ITP is often “manageable” and the risk of death from the disease “very rare”.
He insisted that there was “currently no evidence” that one vaccine against Covid was riskier than another.
Patients who developed ITP averaged 69 years old and often had at least one underlying medical condition, such as heart disease or diabetes.
The first blood clots to alert people given the AstraZeneca vaccine were those that appeared in veins near the brains of younger adults with a condition called CSVT (cerebral sinus vein thrombosis).
However, since then people have developed blood clots in other parts of the body.
All clots were associated with thrombocytopenia, an abnormally low number of blood platelets – an unusual effect as platelets are usually used by the immune system to make the clots.
In most cases, people make a full recovery and the blockages are generally easy to treat if discovered early, but they can cause strokes or heart or lung problems to go unnoticed.
Symptoms depend entirely on where the clot is, with brain blocks causing excruciating headaches. Blood clots in the large arteries in the abdomen can cause persistent stomach pain, and those in the legs can cause limb swelling.
Some countries have decided to discontinue the jab entirely, Denmark and Norway have decided not to introduce it. Other nations have restricted it to certain age groups.
The Oxford vaccine was approved in the UK in December and is recommended for use over 40 years of age
But AstraZeneca’s sting isn’t the only one believed to cause blood clots. Johnson & Johnson’s single-dose vaccine, which has not yet been approved in the UK, has been linked to 28 cases out of more than 10.4 million vaccinations in the US.
Researchers in Germany believe the problem lies in the adenovirus vector – a cold virus that is used to allow both vaccines to get into the body.
Scientists investigating the problem say the complication is “completely absent” with mRNA vaccines like those from Pfizer and Moderna because they have a different delivery mechanism.
Experts from Goethe University Frankfurt and Ulm University in Helmholtz say the AstraZeneca vaccine penetrates the cell nucleus – a lump of DNA in the middle. For comparison, the Pfizer jab penetrates the liquid around it, which acts as a protein factory.
Pieces of coronavirus proteins that make their way into the nucleus can break down, and the unusual fragments are then expelled into the bloodstream, where they can cause clotting in a tiny number of people, scientists claim.
AstraZeneca said in a statement that its Covid vaccine is “highly effective” and will help save over 100,000 lives around the world.
Ensuring the safety of the vaccine is “of the utmost importance” and the company is working with regulators and the scientific community to understand the “extremely rare” blood clots, it said.
The JCVI recommended giving children under 39 years of age a vaccine other than the Oxford vaccine because of concerns about the very low risk of possible links to blood clots. Figures show that over 40 million people in the UK received their first vaccination while over 28 million received their second