As I mentioned in the summary, the AstraZeneca/Oxford vaccine is under some fairly serious scrutiny, with a number of European countries pausing the jab over concerns about blood clots.
The Guardian’s health editor, Sarah Boseley, reports that 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.
But, Boseley writes, while governments are pulling the plug, most scientists are rolling their eyes, because, 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.
So why are countries pausing the jab?
Boseley says one element 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. It was afterwards found that one in 55,000 jabs with a vaccine called Pandemrix caused the sleeping disorder narcolepsy in children. About 100 people in the UK are thought to suffer from the condition, which causes them to fall asleep without warning during the day.
For that reason there will be particularly careful scrutiny of any cases that do not look like ordinary blood clots.
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.
You can read Sarah’s full story here.