France, Germany, Italy and Spain have announced they will resume the roll-out of the Oxford/AstraZeneca vaccine after the European Medicines Agency (EMA) found the vaccine was “not associated” with a higher risk of blood clots.

The EMA reviewed the jab after 13 European countries suspended the use of the vaccine over fears of a link to blood clots.

In the published review, the regulator found the jab to be “safe and effective”.

Some other EU countries, such as Sweden, have not yet decided whether they will re-start the vaccine rollout.

The World Health Organisation (WHO) has also vouched for the shot. In a statement, they said “the benefits of the AstraZeneca vaccine outweigh its risks” and recommends that vaccinations continue.

Putting the risks into perspective

This comes at a time where women all over the world are voicing their concerns that the combined oral contraceptive pill carries significantly higher blood clot risks than the Oxford vaccine.

Research published in The Lancet found that the combined oral contraceptive pill triples the risks of blood clots; a risk which increases with obesity and a family history of blood clots.  

The Food and Drug Administration (FDA) estimates that the risk of birth control users developing a serious blood clot is three to nine women out of 10,000, every year. Comparably, the statistical likelihood of blood clots in those that have had the Oxford AstraZeneca vaccine is 3 in 1,000,000.

For pregnancy and up to six weeks postnatally, the risk of blood clots is 1-2 in every 1,000 women.

Risk of blood clots for:

  • Oxford vaccine: 3 in 1,000,000
  • Combined pill: 3-9 in 10,000
  • Pregnancy + 6 week postnatal: 1-2 in 1,000
  • Women not taking contraception: 2 in 10,000

These statistics puts into perspective how low the risks of developing clots are, after having the vaccine.

As AstraZeneca themselves pointed out, the number of clots reported is actually lower than the “hundred of cases that would be expected” in the general population, independent of the vaccine’s use; quoted as 2 in every 10,000 women not using hormonal contraception.

Anyone with unusual bruising or a headache lasting more than four days after vaccination should seek medical advice

Even so, the EMA have advised that anyone with unusual bruising or a headache lasting more than four days after vaccination should seek medical advice.

This is a precautionary measure that has been put in place due to the very small number of reports of blood clots associated with thrombocytopenia, i.e. low levels of blood platelets (elements in the blood that help it to clot) with or without bleeding, including rare cases of clots in the vessels draining blood from the brain (CVST).

The EMA emphasise that these are very rare cases (3 in 1,000,000). A causal link with the vaccine is therefore not proven, but is possible and “deserves further analysis”.

EMA executive director, Emer Cooke, said: "Drawing attention to these possible rare conditions and providing information to health care professionals and vaccinated people will help to spot and mitigate any possible side effects."

Prof Sir Munir Pirmohamed, chair of the Commission on Human Medicines, added: "Given the extremely rare rate of occurrence of these events, the benefits of the AstraZeneca vaccine, with the latest data suggesting an 80% reduction in hospitalisation and death from Covid disease, far outweigh any possible risks.”

Product information on the vaccine will be updated to include information about rare blood clots.