After more than 18 million people have received vaccinations with AstraZeneca’s jab, Britain’s health regulator said seven people had died due to rare blood clots, although it was unclear whether these are a coincidence.
“The benefits in preventing a 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,” June Raine, chief executive of Britain’s Medicines and Healthcare Regulatory Agency (MHRA) told the BBC.
The MHRA previously said there had been 30 cases of rare blood clot events reported out of the 18.1 million AstraZeneca/Oxford vaccine doses administered in Britain.
As of March 24, a total of 22 cases of cerebral vein thrombosis and eight other types of thrombosis had been reported, the agency said, noting that here too, it was unclear whether these were connected.
However, a scientist said that evidence was growing that the occurrence of a number of rare blood clot events among people who have had the AstraZeneca coronavirus vaccine was causally related.
“It is not uncommon to get clusters of rare events purely by chance,” Paul Hunter, a medical microbiologist at the University of East
Anglia, told the BBC Radio 4 Today programme on Saturday, according to PA news agency.
“But, once you find that cluster in one population and it then crops up in another – such as previously in the German and now in the English – then I think the chances of that being a random association is very, very low.”
“Clearly more work needs to be done, but I think the evidence is shifting more towards it being causally related at the moment.”
However he said that the risks of taking the AstraZeneca vaccine were still far outweighed by the risks of not getting the jab.
“The chance of dying if you don’t have the vaccine is many times greater than the risk of dying from CVT (cerebral venous thrombosis) after the AstraZeneca vaccine, even if it does turn out, as I suspect it will, that this link is causal,” he said.
Reports of unusual blood clot cases in patients who have received the AstraZeneca vaccine have led some national regulators to place restrictions on who can receive the jab.
Canada, for instance, suspended use for those under the age of 55 while Germany has largely halted the jabs for those under 60.
Britain has said the vaccine is safe for all age groups.
The European Medicines Agency, an EU regulator, said the vaccine is safe, although it is planning more consultations in the wake of the decisions by national health officials.
Meanwhile in Britain, more than 31 million people have received the first dose of the vaccination, more than 18 million of them with AstraZeneca.
The number of cases has improved significantly, with the seven-day incidence figure at 55 per 100,000 inhabitants. There has also been a significant fall in the number of daily deaths.