The EMA has received an additional 13 reports of CSVT

Results from the long-awaited US trial of the Oxford-AstraZeneca Covid vaccine are out and confirm that the shot is both safe and highly effective.

More than 32,000 volunteers took part, mostly in America, but also in Chile and Peru.

The vaccine was 79% effective against stopping symptomatic Covid disease and 100% effective at preventing people from falling seriously ill.

And there were no safety issues regarding blood clots.

That should further reassure some EU countries that recently paused rollout of the vaccine amid concerns about a possible link.

Some are already starting to use it again now that Europe's medicines regulator has completed its review and has also concluded the vaccine is safe and effective.

This new trial data may also prove useful in reassuring people about how well the vaccine works to protect the elderly against Covid-19 illness.

Several countries initially would not authorise the use of the vaccine in adults over 65, citing lack of evidence.

Around a fifth of the volunteers in this trial were over 65 and the vaccine - given as two doses, four weeks apart - provided as much protection to them as to younger age groups.

Hundreds of thousands of people in the UK are already receiving the AstraZeneca vaccine every day, so these numbers are tiny by comparison.

But the results are vital for the US and should clear the way for the vaccine to be approved by regulators there within the next month or two.

Lead investigator of the Oxford University trial of the vaccine, Prof Andrew Pollard said: "'These results are great news as they show the remarkable efficacy of the vaccine in a new population and are consistent with the results from Oxford-led trials.

"We can expect strong impact against Covid-19 across all ages and for people of all different backgrounds from widespread use of the vaccine."

Prof Sarah Gilbert, co-designer of the vaccine, said: "In many different countries and across age groups, the vaccine is providing a high level of protection against Covid-19 and we hope this will lead to even more widespread use of the vaccine in the global attempts to bring the pandemic to an end."

Prof Gilbert said there were always cases of people falling ill after receiving a vaccine, particularly when very large numbers of were receiving a jab, but that did not mean that the vaccine was responsible for the problems. Meanwhile thousands of people a day were now dying across Europe from Covid-19.

She said: "It is really important that we get the chance to protect people as quickly as possible. This vaccine will save lives."

There is no evidence the AstraZeneca Covid vaccine causes blood clots, say UK and EU regulators after a "thorough and careful review".

The MHRA and the EMA say people can have confidence in the vaccine's benefits and should get immunised, despite some countries pausing use.

But anyone with a headache lasting more than four days after vaccination should seek medical advice, as a precaution.

The same advice applies if someone develops unusual bruising.

That is because the regulators have received a very small number of reports of an extremely rare form of blood clot occurring in the brain.

It is this type of clot that triggered some European countries to pause rollout of the Oxford-AstraZeneca vaccine.

In the UK, five cases of cerebral sinus vein thrombosis (CSVT), among 11 million people who have received the vaccine, occurred in men aged between 19 and 59. One of these was fatal.

The EMA has received an additional 13 reports of CSVT.

CSVT can occur naturally and no link to the vaccine has been established. The patients also had low blood platelet counts - cells involved with clotting.

Covid infection can make clots more likely.

Dr June Raine, chief executive of the MHRA, said regulators would continue to closely monitor the situation and people should have the vaccine when it is their turn: "The public can have every confidence in the thoroughness of our review."

Prof Sir Munir Pirmohamed, chair of the Commission on Human Medicines, said the gains from getting vaccinated were clear.

"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," he said.

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

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."

The EMA review, based on data from around 20 million people vaccinated, concluded:

the benefits of the vaccine in combating the still widespread threat of Covid-19 - which itself results in clotting problems and may be fatal - continue to outweigh the risk of side effects

the vaccine is not associated with an increase in the overall risk of blood clots (thromboembolic events) in those who receive it

there is no evidence of a problem related to specific batches of the vaccine or to particular manufacturing sites

the vaccine may be associated with very rare cases of brain clots and clots in multiple blood vessels (known as disseminated intravascular coagulation or DIC - the EMA has received seven reports of this so far)

It said any of the following symptoms after vaccination should prompt a medical check as a precaution:

breathlessness

pain in the chest or stomach

swelling or coldness in an arm or leg

severe or worsening headache or blurred vision after vaccination

persistent bleeding

multiple small bruises, reddish or purplish spots, or blood blisters under the skin

These occur very rarely and are different to the common side-effects people can expect with any vaccine, such as some tenderness where the injection was given.