What’s happened now?
On Tuesday, Germany’s Stiko vaccine committee advised against using the Oxford-Swedish vaccine in the under-60s in Germany because of concerns that current data showed serious clotting side effects in that population.
Chancellor Angela Merkel said the “very rare but very serious cases of thrombosis” in people who had been vaccinated with AstraZeneca could not be ignored.
This comes barely a week after the country reversed its previous suspension of the jab after the European Medicines Agency deemed the vaccine safe and effective against Covid-19.
So the vaccine isn’t suspended as such?
That’s right. It’s a national recommendation rather than a suspension. People under 60 can still decide to have the AstraZeneca vaccine if they’d like to, but only after consultation with the vaccinating doctor and based on an individual risk analysis.
What about if you’re under 60 and due for your second jab with AstraZeneca?
If your doctor clears you to have it, you can choose to take it if you’d like to, or you can wait for the vaccine committee to make its recommendation on this. This is expected by the end of April.
So could I have my second jab with a different vaccine?
Stiko will clarify this at the end of April, but perhaps. In the UK, there is a trial underway examining whether giving people different Covid vaccines for their first and second doses is as effective as giving the same type twice. However, there are no results on this available yet.
Although the UK’s official guidance is to give the same brand for both jabs, Public Health England said earlier this year that different ones could be used in rare circumstances, such as if the same vaccine wasn’t available or it was not known which brand was used for the first dose.
And some scientists believe that mixing and matching the vaccines – as is already done for diseases such as Ebola – could even boost immune response.
Tell me about this rare clotting side effect…
Some people who’ve had the AstraZeneca vaccine have developed a rare condition called cerebral sinus venous thrombosis, or CSVT, a rare type of blood clot in the vein that’s responsible for draining blood from the brain. The clot prevents the blood from flowing out, which can lead to bleeding on the brain and stroke.
The jury is out on exactly why this is happening – and whether the vaccine is definitely implicated – but in a recent safety report, medical regulator the Paul Ehrlich Institute reported a “noticeable cluster” of these cases occurring soon after patients had had the AstraZeneca jab.
I’ve had the AstraZeneca jab, should I be worried?
It’s important to remember that this problem has not been proven to be linked to the vaccine and has only affected a tiny number of people out of the very many who have been vaccinated.
However, if you experience the below symptoms between 4 and 20 days after having a vaccination (or any other unusual or severe symptoms), you should seek immediate medical attention mentioning your recent vaccination.
How many cases of CSVT have there been in Germany?
As of Monday, 31 suspected incidences of cerebral sinus venous thrombosis in people who had been vaccinated with AstraZeneca had been reported to the Paul Ehrlich Institute.
A total of 19 of those also had a low platelet count (thrombocytopenia) and, sadly, nine were fatal. With the exception of two men (36 and 57), all the cases affected women between the ages of 20 and 63.
How many vaccinations with AstraZeneca have been given in Germany?
According to the Robert Koch Institute (RKI), around 2.7 million first jabs and 767 second doses had been given as of Monday.
So, it’s a serious but very rare problem?
Yes, exactly. The latest figures from the Paul Ehrlich Institute show that there have been around 1.15 cases per 100,000 vaccinations given.
If it’s so rare why is it a problem?
Because it seems to be affecting more people than you would expect. In the US general population, such a rare problem normally affects just five people in every 1 million per year, according to the John Hopkins University.
Why are the under-60s most affected?
We don’t know. It’s possible that this could actually be a reflection of the population the vaccine was most used in. The AstraZeneca jab has been used in younger people to a greater extent than other brands in much of Europe. This is because many countries – including Germany – didn’t sanction the vaccine for use in the over-65s until later because of a lack of study data for that population.
Do we know what’s causing the clots?
This is something that is currently being widely researched, but there is no definitive answer as yet.
Some scientists have suggested the vaccine could trigger an unusual auto-immune response in a tiny number of people.
I’ve read about HIT, what’s that?
HIT or heparin-induced thrombocytopenia is a rare side effect that occurs in some patients who’ve been given a blood-thinning drug called Heparin.
So what’s the connection to the vaccine?
A team of German researchers, led by clotting specialist Andreas Greinacher of the University of Greifswald, looked at blood samples from nine affected individuals and noted that the symptoms they experienced after vaccination – clotting and a low platelet count – were similar to those seen in HIT.
The German findings suggest that in a small proportion of people, like in HIT, the vaccine may be triggering the immune system to produce a type of antibody that activates platelets, key cells in the body’s blood-clotting mechanisms. These antibodies attack the platelets and, in response, the body produces too many, causing clotting.
A team of Norwegian researchers came to a similar conclusion after examining three cases of blood clots after the vaccine.
However, these findings have not been peer-reviewed or published yet and, as other scientists have pointed out, two of the patients in the analysed group had a history of blood-clotting problems. It is also unclear whether any of the patients had had any previous infection with Covid-19, which itself is a risk factor for blood-clotting disorders.
Essentially, there’s a lot we still don’t know.
How often does this problem happen with Heparin?
More frequently. Some 1-5 percent of patients on Heparin develop CVST compared with the just over 1 in 100,000 suspected cases following the vaccination.
Can CVST be treated?
Yes, providing it’s identified promptly.
So is this definitely happening because of the AstraZeneca vaccine?
No. We don’t know whether the vaccine is causing these side effects yet or not. However, researchers – including those at the Paul Ehrlich Institute – are carrying out further investigations.
As the head of the UK’s medical regulator MHRA Dr June Raine has said, the type of blood clots seen in those who received the vaccine could have been caused by Covid itself.
Yes, and can’t Covid-19 itself cause a drop in platelets?
It can. A 2020 study of Covid-19 patients in China found that cases of thrombocytopaenia were more common in patients with severe Covid. The lower a patient’s platelet levels, the higher their expected mortality rate.
What does this mean for the vaccination rollout?
Germany’s already been widely criticised for the slow speed of its vaccination campaign (official figures show that around 11 percent of the population have received a first dose so far), and this isn’t going to help that.
The below chart shows the percentage of people who have received at least one vaccine dose in Germany compared to the UK.
Health minister Jens Spahn acknowledged that this development was “without question a setback”, but said that Germany still expected to offer every adult a coronavirus jab by September 21st, saying the AstraZeneca jab could now be used more quickly in the over-60s age group.
Have the other vaccines caused any problems?
Yes. There have been around 20 similar cases in the US after vaccination with the Moderna and Pfizer brands, including at least one death. Several of the affected patients had had thrombocytopenia in the past. However, this is out of the over 20 million people who had received at least one vaccine by early February.
Thrombocytopenia is also a well-known side effect of several long-established vaccines, such as those against mumps, measles, rubella and varicella, as well as after natural infection with viruses like HIV and hepatitis C, MedPage Today reported.
What are the World Health Organisation and the European Medical Agency saying?
Both have deemed the AstraZeneca vaccine safe and effective against Covid-19. After recent investigations into the vaccine, they said the overall risk for clotting with this vaccine was no higher than in the general population.
The EMA said that it couldn’t definitively rule out a link between vaccination and these very rare events, but felt that due to the severity of Covid-19, the vaccine’s benefits outweighed its potential risks.
At the same time, it said that more information and advice for healthcare professionals and the public on the potential side effects should be included in the vaccine’s product information. The information and consent sheet given to patients having the vaccine now includes this (as below).
The medical regulator’s safety committee, PRAC, is continuing to assess the cases that have been reported and the outcome of its findings are expected during its plenary meeting on April 6th – 9th.
What’s happening in other countries?
On Monday, Canada recommended stopping the use of AstraZeneca in adults under 55 while cases of CSVT were being investigated.
France is still only using AstraZeneca for the over-55s, while Spain said on Tuesday that it would extend its use to the over-65s. It had previously only been used in the 18-to-65 age group.
Last week, Norway extended its suspension of the Oxford-Swedish vaccine until April 15th, to give health officials more time to investigate any link between the clotting problems and the vaccine. Denmark also extended its suspension of the vaccine.
And Sweden restarted jabs with AstraZeneca this week, but only in the over-65s. Finland only administers the jab to the over-65s and Iceland to the 70s and over.
What about the UK where they’ve vaccinated large numbers of people?
Unlike its European neighbours, the UK has delivered the AstraZeneca vaccine continuously.
Up to mid-March, the UK’s medical regulator MHRA had received five reports of cerebral sinus venous thromboses together with lowered platelets in people who had had the vaccination, including one death. This was out of 11 million doses administered, putting the risk rate well below that of dying of Covid.
However, unlike the picture seen in much of Europe, the cases were all men, aged between 19 and 59.