Blood clots should be listed as a 'very rare' side effect of AstraZeneca jab: EU regulator

7 April 2021, 15:20 | Updated: 7 April 2021, 22:11

Unusual blood clots should be listed as a "very rare" side effect of the AstraZeneca Covid vaccine, the European Medicines Agency has found.

However, the overall benefits of the vaccine in preventing Covid-19 "outweigh the risks of side effects", the organisation said, and evidence shows the vaccine is overwhelmingly safe, with both regulators acting out of caution.

It has listed a series of symptoms that patients who receive the jab should seek immediate medical help for, including shortness of breath, chest pain and swelling in the leg.

The European Medicines Agency (EMA) added that most of the blood clot cases had occurred in women under 60 within two weeks of receiving the vaccine, and suggested the issue came from an immune response.

Read more: UK regulator holds news conference on Oxford/AstraZeneca Covid-19 jab

'Unusual blood clotting should be listed as a possible side effect of AstraZeneca vaccine'

"The currently available data did not allow us to identify a definite cause," an EMA official said. Further studies will be carried out.

Under 30s in the UK will be offered an alternative vaccine, the UK's Medicines and Healthcare products Regulatory Agency (MHRA) also said on Wednesday.

Boris Johnson, who defended the jab on Tuesday, said on the vaccination programme: "You can really start to see some of the benefits of that - it's pretty clear that the decline in the number of deaths, the decline in the number of hospitalisations is being fuelled, is being assisted, the steepness of that decline is being helped by the roll-out of the vaccines so it's very important for everybody to continue to get your second jab when you're asked to come forward for your turn."

The EMA's findings follow the University of Oxford's pausing of trials on children with the jab as the UK's MHRA investigates the potential association between the jab and clots.

The EMA said it "is reminding healthcare professionals and people receiving the vaccine to remain aware of the possibility of very rare cases of blood clots combined with low levels of blood platelets occurring within two weeks of vaccination".

"So far, most of the cases reported have occurred in women under 60 years of age within two weeks of vaccination.

"Based on the currently available evidence, specific risk factors have not been confirmed."

Read more: Former head of UK vaccines regulator: 'No reservations' about AstraZeneca jab

Other symptoms patients should get help for are persistent abdominal pain, neurological symptoms like severe and persistent headaches or blurred vision, and tiny blood spots under the skin beyond the site of the injection, the EMA added.

AstraZeneca said: "Neither agency identified any risk factors, such as age or gender, or a definite cause for these extremely rare events.

"However, they came to the view that these events have a possible link to the vaccine and requested they be listed as an extremely rare potential side effect.

"Overall, both of these reviews reaffirmed the vaccine offers a high-level of protection against all severities of COVID-19 and that these benefits continue to far outweigh the risks.

"AstraZeneca has been actively collaborating with the regulators to implement these changes to the product information and is already working to understand the individual cases, epidemiology and possible mechanisms that could explain these extremely rare events."

The World Health Organisation said a blood clots link was plausible but unconfirmed.