As France and Germany join Ireland, Norway, Denmark and the Netherlands in suspending the use of the Oxford/AstraZeneca vaccine – even though the European Medicines Agency and the World Health Organization are advising people to continue taking it – the common refrain in European governments is that they are acting out of “an abundance of caution”.
There have been a handful of reports of blood clots in people recently vaccinated and also a rarer condition called thrombocytopenia, in which people do not make enough platelets. That can result in excessive bleeding. Deaths have been reported in Austria and Italy, which stopped the use of one batch of vaccine for fear it was contaminated. Meanwhile a further death from thrombocytopenia has been reported in Norway, as well as three hospitalisations.
While governments are pulling the plug, most scientists are rolling their eyes. The EMA and WHO are investigating the incidents, but so far there is no evidence that any were caused by the vaccine.
Experts say that the numbers of blood clots and thrombocytopenia cases in people who have been vaccinated is no higher than in the population that has not received the jab. The International Society on Thrombosis and Haemostasis, representing medical experts around the world, said on Friday that “the small number of reported thrombotic events relative to the millions of administered Covid-19 vaccinations does not suggest a direct link”.
Blood clots are common, they said, but not more common in people who have had a Covid jab, from evidence so far. They recommended that even people with a history of blood clots or taking blood-thinning drugs should go and get their vaccination.
In the UK, the Medicines and Healthcare products Regulatory Authority and the Joint Committee on Vaccination and Immunization (JCVI), which advises the government, have both been robust. “The UK has administered 11m doses of the AstraZeneca vaccine and there has been no demonstrable difference in the number of blood clots since the vaccine was introduced,” said Prof Anthony Harden, the JCVI deputy chair. The MHRA said it was working closely with its international counterparts and reviewing the cases, but “the evidence available does not suggest the vaccine is the cause”.
AstraZeneca itself says there have been 15 deep vein thrombosis (DVT) events and 22 pulmonary embolisms (blood clots in the lungs) across the whole of the EU and UK up to 8 March. “This is much lower than would be expected to occur naturally in a general population of this size and is similar across other licensed Covid-19 vaccines,” it said in a statement.
But these protestations appear not to be cutting much ice with European governments. There are a number of other factors that may be in play.
One is that nobody can rule out very rare side-effects on the basis of trials involving tens of thousands of people. There was such an issue during the swine flu pandemic of 2009. A study later found that one in 55,000 jabs with a vaccine called Pandemrix caused the sleeping disorder narcolepsy in children.
For that reason there will be particularly careful scrutiny of any cases that do not look like ordinary blood clots. In Denmark, a 60-year-old who died was said to have had “highly unusual” symptoms. Norway also said the three people being treated in hospital had “unusual symptoms”.
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And governments, unlike scientific bodies, have to weigh up other things besides evidence. They will worry about public confidence – in the vaccine and also in ministers’ handling of any concerns. France for instance has struggled over vaccination. There is a long history of public suspicion of drug companies, which contributed to a debacle over the swine flu vaccine. France bought millions of doses, which people turned down. It has low vaccination rates for measles, mumps and rubella jabs in children too.
Germany, meanwhile, was the first country to refuse to allow people over the age of 65 to have the AstraZeneca vaccine because of the absence of evidence of how well it worked in older people, indicating a more cautious approach than most.
But the other factor in deciding on suspension could even be supply. In the UK, there are plentiful stocks. In Europe, there are not. AstraZeneca has just cut its proposed deliveries again, down to 30m doses in the first quarter, which is about a third of what was originally promised. Suspending the vaccine is easier in Europe if it is not available in great quantities anyway.