What we know about blood clots, side effects and risks
What did the regulators say?
A review by the EMA safety committee concluded that “unusual blood clots with low blood platelet counts should be listed as very rare side effects” of the AstraZeneca vaccine.
Emer Cooke, Executive Director of EMA, said: “The risk of death from Covid is much greater than the risk of death from these side effects.”
The MHRA said the vaccine still had huge benefits in preventing Covid-19 and serious illness, but added that due to a very small number of blood clots in younger people, people from under 40s will be offered instead of Pfizer or Moderna jabs.
Dr June Raine, Managing Director of the MHRA, added: “Anyone who exhibits symptoms four or more days after vaccination should see a doctor promptly – a new onset of a severe or persistent headache or blurred vision. , shortness of breath, chest pain, leg swelling, persistent abdominal pain, or even unusual skin bruising or spot spots beyond the injection site. “
How did other countries react?
Germany, the Netherlands, Sweden and Canada have restricted the use of the AstraZeneca vaccine in young people. Italy and Spain have stopped the use of the jab in people under the age of 60.
Denmark announced on April 14 that it would stop administering the Oxford / AstraZeneca Covid-19 vaccine fully following its link to very rare cases of blood clots, a decision based on low levels of Covid-19 in country and caution regarding the rare side effect. .
The move, which at least for now removes the vaccine from Denmark’s immunization program, could delay the rollout of the vaccine in the country for up to four weeks, based on previous statements from health agencies.
France said those under 55 who received a first dose of AstraZeneca should take a different vaccine for the second. Olivier Véran, the country’s health minister, said the new advice would be that Moderna and Pfizer vaccines be used for their second dose.
Spain will study the effects of mixing different vaccines against the coronavirus, government researchers said on April 19, in response to evolving guidelines on shooting safety for the AstraZeneca.
Additionally, Australia has doubled its order for the Pfizer Covid-19 vaccine, as the country rushes to revise its inoculation plan amid concerns about the risk of blood clots with the AstraZeneca vaccine.
Many decisions to restrict the use of the jab must also be seen in the context of a country with access to other jabs and low rates of Covid.
What did AstraZeneca say?
In March of this year, AstraZeneca said it was analyzing its database to understand “whether these very rare cases of blood clots associated with thrombocytopenia (low platelet count) occur more frequently than one would naturally expect. in a population of millions of people “. .
Meanwhile, on April 6, a trial of the Oxford / AstraZeneca vaccine in children was suspended, but the scientists involved said there were no safety concerns with the trial itself and that they were awaiting further information from the MHRA.
In response to these concerns, a study from the University of Oxford looked at the impact of blood clotting on the brain in coronavirus patients and AstraZeneca recipients, finding that the occurrence of brain clots due to the coronavirus was eight times the risk presented by the AstraZeneca jab.
Sir John Bell, professor of medicine at the University of Oxford, has said he expects all vaccines to have “some background level of clotting problems”. Professor Sir Bell went on to say that data on this issue is still being collected for further study.
What about the Johnson and Johnson vaccine and blood clots?
Regulators in the United States have suspended the deployment of the Johnson and Johnson vaccine after six people suffered from blood clots two weeks after receiving the vaccine – one person died. Regulators say the decision is based on an “abundance of caution” and have since resumed jab use after a safety review.
The decision is already being felt more widely: the company has delayed shipments of the vaccine to Europe. And South Africa, which has decided to stop using the AstraZeneca vaccine due to a lack of efficacy against a new variant, has also put its campaign on hiatus.
On April 20, the European Medicines Agency (EMA) said there was a possible link between Johnson & Johnson’s Covid-19 vaccine and rare blood clots, but said the benefits of the J&J vaccine were far outweighed the risks and that new investigations would continue.
What are the side effects of the Oxford / AstraZeneca vaccine?
AstraZeneca vaccine lists the following side effects that may occur after the bite: tenderness, pain, heat, itching or bruising at the injection site, generally feeling unwell, feeling tired, chills or fever, headache, nausea , joint or muscle pain.
Ian Douglas, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, explains that these side effects are “quite common” and occur in more than one in 10 people who receive the vaccine.
When should I see a doctor?
While some people will experience side effects from the jab, experts have said that certain symptoms may be a sign of a more serious condition that needs immediate medical attention.
Professor Beverley Hunt, medical director of the Thrombosis UK charity, said thrombosis in the head can present as an extremely severe headache.
“We have seen patients who had thrombosis in the head or abdomen since about the fourth day after the vaccine,” she said.
“I think it’s very important to tell people that a lot of people experience side effects from the AstraZeneca vaccine and they usually set in on the fourth or fifth day.
“What we saw were people who had the worst headache they ever had on day four and they turned out to have thrombosis in the large vein in their head.”
What factors increase the risk of blood clots?
Blood clots are rare in young and healthy people. Below is a list of factors that can make them more common, although it is not clear if these factors are involved in post-vaccination events, which are a specific type of clot that occurs alongside low platelets. . In fact, hematologists have said that there is currently no evidence that these groups are at greater risk for this side effect.
Usually, you are more likely to have a blood clot if you:
- You are staying or have recently been discharged from hospital – especially if you cannot move around a lot (such as after an operation)
- Are overweight
- You are using combined hormonal contraception such as the combined pill, birth control patch or vaginal ring
- Have ever had a blood clot
- Are pregnant or have just had a baby
- Have an inflammatory disease such as Crohn’s disease or rheumatoid arthritis
What other vaccines are available?
The UK is currently using two vaccines, Pfizer / BioNTech and Oxford / AstraZeneca, while a third coronavirus vaccine, Moderna jab, began rolling out in Wales on April 7.
Meanwhile, preliminary results announced on April 6 from trials of the Valneva Covid-19 vaccine, which is expected to be manufactured in the UK, showed that it produces a “strong immune response”, paving the way for a clinical trial of phase three.