UK medicines regulator insists AstraZeneca vaccine safe to use and says no evidence of link to blood clots

MHRA also investigating ‘extremely rare’ type of blood clotting within brain of five people who received vaccine

The UK medicines regulator has insisted that the AstraZeneca vaccine is safe to use and that there is no evidence of a link to the blood clots that have been reported in some recipients of the jab.

The Medicines and Healthcare products Regulatory Agency said that the benefits of the vaccine in preventing Covid-19 far outweigh any associated risks.

It added that it was investigating an “extremely rare” type of blood clotting within the brain of five people in the UK who received the vaccine, though no causal link has been made to the jab.

These ‘thromboembolic events’ have also been recorded in Germany and Norway, both of which have suspended use of the vaccine amid ongoing reviews.

The MHRA intends to closely assess five reports of men aged 19 to 59 who experienced a clot in their cerebral veins together with lowered blood platelet counts. One of the five has since died.

The regulator said it was looking at the cases but stressed the events are very uncommon and there was a possibility they could have been caused by Covid itself.

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It said that use of the vaccine, which has so far been administered to roughly 11 million people in the UK, should continue while the five reports were investigated.

"The available evidence does not suggest that blood clots in veins (venous thromboembolism) are caused by Covid-19 Vaccine AstraZeneca," the MHRA said.

"A further, detailed review into five UK reports of a very rare and specific type of blood clot in the cerebral veins (sinus vein thrombosis) occurring together with lowered platelets (thrombocytopenia) is ongoing."

While this condition has so far been reported at a rate of less than one case per one million vaccinated people, the risk of dying from Covid-19 for those aged 40 to 49 is one in 1,000, the MHR said.

Dr Phil Bryan, MHRA vaccine safety lead, said: "Where we are now is that no proven causal association with what is still an extremely rare medical event has been proven for the AZ vaccine.

"But we do know that these are highly effective vaccines. We still have a huge burden of Covid disease in the population.

"So, right now, the balance of benefits and known risks of the vaccine are favourable."

Munir Pirmohamed, Chair of the Commission on Human Medicines, suggested that even if a link between the clots and the vaccine was established, the benefits of the jab would continue to outweigh the risk.

“If we feel that there’s causal link then we may need to update the product information, but overall, I don’t think that would necessitate pause to any kind of vaccination programme,” he said.

The MHRA said anyone with a headache that lasts for more than four days after vaccination, or bruising beyond the site of vaccination after a few days, should seek medical attention.

France, Spain and Italy – along with many other countries – are similarly investigating the vaccine after 37 people who received a first dose, out of some 17 million recipients in Europe, later went on to experience a thromboembolic event.

AstraZeneca said the incidence of such conditions is much lower than would be expected to occur naturally in a general population of this size and is similar to that of other licensed Covid-19 vaccines.

The European Medicines Agency is conducting its own review into the vaccine, the findings of which are due to be announced later today.

The MHRA’s announcement comes as health secretary Matt Hancock said a batch of 1.7 million doses had been delayed in the last week due to the need to retest its stability.

“Events like this are to be expected in a manufacturing endeavour of this complexity and this shows the rigour of our safety checks,” he told MPs.