The European Medical Agency (EMA) has said blood clots can be a “very rare side effect” of the AstraZeneca vaccine against Covid-19.

The medical regulator’s statement comes after weeks of uncertainty in countries across the world, with some nations suspending the vaccine’s use temporarily and others re-commencing its distribution.

Whilst making today’s statement that a link between clotting and the vaccine does exist, the EMA said it would not support banning the injection because the danger posed by Covid-19 is greater than that of any potential side-effects from the inoculation.

The EMA found 169 blood clots in the brain known as CVST, and a further 53 splanchnic vein thrombosis clots, following 34 million vaccine doses, giving a rate of 1 clot per 150,000 doses.

“EMA’s safety committee has concluded today that unusual blood clots with low blood platelets should be listed as very rare side effects (of the AstraZeneca injection),” the medicines regulator said.

“One plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin.”

The EMA’s executive director Emer Cooke told reporters however that “the benefits of the AstraZeneca vaccine in preventing Covid-19 overall outweigh the risks of side effects.”

“Covid-19 is a very serious disease with high hospitalisation and death rates and everyday Covid is still causing thousands of deaths across the EU,” she said.

“This vaccine has proven to be highly effective – it prevents severe disease and hospitalisation, and it is saving lives.

“Vaccination is extremely important in helping us in the fight against Covid-19 and we need to use the vaccines we have to protect us from the devastating effects.

“The PRAC, after a very in-depth analysis, has concluded that the reported cases of unusual blood clotting following vaccination with the AstraZeneca vaccine should be listed as possible side effects of the vaccine.”

Most of the recorded blood clots were experienced by females under 60 within 14 days of vaccination.

In response, the British government has announced it will cease giving the AstraZeneca vaccine to people under 30, despite the EMA advising against any bans based on age or sex.