The British Society for Haematology decided to act after some experts became concerned at the number of cases of blood clotting linked to a rare syndrome known as thrombocytopenia.
It said doctors needed to be “on alert” for the condition and what to look for, how to treat it and how to report cases so the data can be properly collated.
Doctors have been issued with new advice to help them spot a rare blood-clotting disorder that may be linked to the Oxford-AstraZeneca coronavirus vaccine, as the UK’s medicines regulator confims seven deaths.
Thrombocytopenia involves patients having abnormally low numbers of platelet cells in their blood. Platelets help blood to clot after an injury.
In the affected patients, doctors are finding blood clots, particularly in the brain, that are thought to be caused by platelets attaching to antibodies.
It is normally seen in some patients who receive the blood-thinning medication heparin, but cases linked to the Oxford-AstraZeneca vaccine are occurring in patients without the presence of that drug.
On Thursday, the UK’s medicines regulator said it had identified 30 cases out of more than 18 million doses of the vaccine. Seven of the cases were fatal, the regulator said.
Any link, if one is proven, would still be extremely rare and mean the vaccine was still safe for people to receive.
It would represent far less of a risk than the coronavirus itself, which is known to significantly increase the risk of blood clots.
The Medicines and Healthcare products Regulatory Agency (MHRA) is reviewing all the reported cases but urged members of the public to continue getting the jab to protect them against Covid-19.
In Europe, detailed information has been released about the suspected cases, but in the UK, the regulator has so far not released any in-depth information about the individuals affected by the syndrome.
The MHRA is reliant on reports of any possible side effects being made via its yellow card reporting system. Just because a report has been made, it does not mean the vaccine was the definite cause of any side effect.
The British Society for Haematology told doctors the syndrome was “being noted after coronavirus vaccination and is highlighted as affecting patients of all ages and both genders; at present, there is no clear signal of risk factors.”
It added: “Clinicians need to be on alert for this syndrome, to understand how to make the diagnosis and to note the specifics of how to treat it.”
In an interview with The Independent, Adele Fielding, a consultant haematologist and president of the British Society for Haematology, said the alert was sent out after doctors contacted her concerned about what they were seeing.
“We felt that it was sufficiently important that we should make this public and make sure that everybody was aware. Any link with the coronavirus vaccine is not for us to determine.
“But what it is for us to do is to highlight the issue so that people are well aware of it. To make sure this is recognised, because it may present in different ways to different professionals, and we want to be sure nobody misses it, and that nobody feels they don’t know where to go for advice and help.”
