Blood clots potentially linked to vaccines ‘extraordinarily rare events’

Aine Fox and Sam Blewett, PA
·3-min read

A scientist advising the Government has insisted blood clots potentially associated with coronavirus vaccines are “extraordinarily rare events” and reminded the public that no medicine is completely free of side-effects.

Professor Peter Openshaw’s comments come after the European Medicines Agency (EMA) said it is continuing to look at reports of rare blood clots related to the vaccine from Janssen, whose parent company is Johnson & Johnson.

The vaccine is yet to be approved for use in the UK, but the Government has ordered 30 million doses.

Prof Openshaw, a member of the Covid-19 clinical information network, told BBC Radio 4’s Today programme: “We still don’t know whether they are directly related and caused by the vaccine but it seems possible that they could be.

“We still have to bear in mind just how rare these events are, and we’re doing something at massive scale in terms of rolling out these vaccines, and there are many vaccines around.

“It wouldn’t be surprising to find the J & J, the Janssen vaccine, also causes rare blood clots, because it’s based on an adenovirus technology which is not that far away from the technology which is being used in the AstraZeneca vaccine.”

Four serious cases of unusual blood clots with low blood platelets have been reported in relation to the Janssen jab – one in a clinical trial and three during the vaccine’s rollout in the US. One person has died.

It follows the EMA announcement earlier this week that brain blood clots with low platelet count should be regarded as a rare side-effect of the Oxford/AstraZeneca vaccine.

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In the UK, regulators have recommended that people aged 18 to 29 should be offered alternatives to the AstraZeneca vaccine, saying there was a possible link between the jab and “extremely rare” blood clots.

The Medicines and Healthcare products Regulatory Agency (MHRA) said the benefits still outweigh the risks overall, but while it has not concluded that the AstraZeneca vaccine causes rare brain clots, it said the link is getting firmer.

The MHRA said figures suggest the risk of rare blood clot is the equivalent to four people out of every million who receive the AstraZeneca vaccine.

Asked if he is concerned public confidence in jabs could be undermined, Prof Openshaw said: “These are extraordinarily rare events and there is no medicine that is going to be completely free of side-effects.

“But this is on the scale of the risk of adverse outcome that you would expect if you were to get in the car and drive 250 miles, and many of us wouldn’t blink before taking that risk.

“So I think it really is important to recognise just how rare these events are.”

The EMA is also looking at five reports of rare capillary leak syndrome in people who were vaccinated with AstraZeneca.

This syndrome causes leakage of fluid from blood vessels, causing tissue swelling and a drop in blood pressure.

A spokesperson for the MHRA said: “We are reviewing these reports carefully.

“We continue to work closely with international counterparts, including the EMA, in understanding the global safety experience of Covid-19 vaccines.”

Asked about the Janssen vaccine, the MHRA said it remains under review.