The AstraZeneca COVID-19 vaccine remains in the spotlight as rare blood clotting cases add up in the UK and France, while some governments in Europe have restricted its use to only older people.
Britain's medicines regulator is urging people to continue taking the AstraZeneca vaccine despite revealing that seven people in the UK have died from rare blood clots after getting the jab.
The Medicines and Healthcare Regulatory Agency said it wasn't clear if the shots are causing the clots, and that its "rigorous review into the UK reports of rare and specific types of blood clots is ongoing".
The MHRA said seven people had died as a result of developing blood clots, although it didn't disclose any information about their ages or health conditions.
In total, the agency said it had identified 30 cases of rare blood clot events out of 18.1 million AstraZeneca doses administered up to March 24.
The risk associated with this type of blood clot is "very small", it added.
"The benefits of COVID-19 vaccine AstraZeneca in preventing COVID-19 infection and its complications continue to outweigh any risks and the public should continue to get their vaccine when invited to do so," said the agency's chief executive Dr June Raine said.
Concerns over the AstraZeneca vaccine have already prompted some countries to restrict its use to older people, including France, Germany, Sweden and the Netherlands.
The jab remains suspended in Denmark.
In France, four people have died after suffering blood clots after getting the AstraZeneca vaccine, while there have been clotting events in total.
The family of a 38-year-old woman who died after suffering blood clots in the brain filed a criminal complaint in Toulouse on Saturday seeking a manslaughter investigation.
France's national medicine safety agency says it is investigating all cases, while the country has restricted use of the AstraZeneca vaccine to people over 55.
The European Medicines Agency shares the view that the benefits of the vaccine outweigh the risks.
It has said a causal link between unusual blood clots in people who have had the AstraZeneca vaccine is "not proven, but is possible".
The World Health Organisation has also urged countries to continue using the jab.
The UK, which has rolled out coronavirus vaccines faster than other European nations, is particularly reliant on the AstraZeneca vaccine, which was developed by scientists at the University of Oxford.
It has also been using the vaccine developed by Pfizer, from which the agency has not seen any reported blood clot events.
The UK has given a first vaccine dose to 31.4 million people, or around 46 per cent of its population, figures on Saturday showed.
That's a much higher rate than the rest of Europe. Delivering second doses is the priority for April.
The relative success of the country's vaccination program has been credited for helping to sharply reduce new coronavirus infections in the UK after a winter surge, paving the way for a modest easing of lockdown restrictions on gatherings.
Despite the improvement, the UK has recorded Europe's highest COVID-related death toll, with more than 126,500 deaths.
University of Bristol pediatrics professor Adam Finn said the "extreme rarity" of the blood-clotting events in the context of the millions of jabs administered in the UK makes the decision very straightforward.
"Receiving the vaccine is by far the safest choice in terms of minimising individual risk of serious illness or death," he said.
Australian Associated Press
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