European regulators have authorised AstraZeneca's coronavirus vaccine for use in adults throughout the European Union.
The European Medicines Agency (EMA) licensed the vaccine to be used in people 18 and over, though concerns had been raised this week that not enough data exist to prove it works in older people.
The shot is the third Covid-19 vaccine given the green light by the European Medicines Agency, after ones made by Pfizer and Moderna. Both were authorised for all adults.
The decision requires final approval from the European Commission, a process that occurred swiftly with the other vaccines.
"There are not yet enough results in older participants (over 55 years old) to provide a figure for how well the vaccine will work in this group," the regulator said, but added that "protection is expected, given that an immune response is seen in this age group and based on experience with other vaccines.
"EMA's scientific experts considered that the vaccine can be used in older adults," the agency said.
Many countries on the continent have been struggling to vaccinate people as quickly as the UK, Israel, the US and elsewhere, and it was long hoped that the AstraZeneca shot would help speed things up at a time when countries face surging cases in a pandemic that has taken the lives of more than 400,000 people in the 27-nation bloc.
The EU bet heavily on the shot, which is cheaper and easier to handle than some other vaccines, with orders for 300 million doses to be delivered after authorisation and options for another 100 million doses.
Emer Cooke, the head of the EMA, said it was "a real pleasure" to authoriSe the vaccine.
"None of them is a magic wand on its own, but together they provide tools and options to prevent different aspects of the disease," she said.
While the AstraZeneca vaccine has been authorised for all adults in other countries, only 12% of the participants in its research were over 55 and they were enrolled later, so there has not been enough time to get results.
But some doctors warned that restricting the vaccine's use in older people might worsen the pandemic's impact, since older people have suffered more severe disease and died at a higher rate from the coronavirus.
In its decision today, the EMA assessed four trials in the UK, Brazil and South Africa.
The agency said the research showed the vaccine proved to be about 60% effective by reducing the number of people who got sick.
The trials have not yet shown whether the vaccine can stop disease transmission.
A separate study testing the AstraZeneca vaccine in the US is still under way.
Professor Andrew Pollard, director of the Oxford Vaccine Group that developed the shot together with AstraZeneca, welcomed the decision.
"The recommendation by the European Medicines Agency is an important milestone in extending access to the Oxford/ AstraZeneca vaccine in our region and providing further endorsement that, after the rigorous scrutiny of regulators, the vaccine can be used to help protect populations from the coronavirus pandemic," he said in a statement.
The EU has particularly lashed out at AstraZeneca after the drugmaker said it would supply less vaccine in a first batch than originally anticipated.
Exacerbating concerns about supplies to the bloc, which is home to some 450 million people, Moderna told countries including Italy and Denmark the company would be delivering fewer vaccines than originally expected.
Jens Spahn, the German health minister, said on Friday he understood many were waiting impatiently for the vaccine, but cautioned that "several hard weeks of vaccine shortage still lie before us".
Before the EMA announcement, Mr Spahn had said Germany would use the regulator's recommendation to decide whether the AstraZeneca vaccine should only be given to people aged 18-64 for now, as suggested in a draft recommendation by the country's independent vaccine advisory committee.
Britain's medicines regulatory agency also acknowledged the limited data in older people but still cleared the shot last month for all adults, with some caution for pregnant women.
The AstraZeneca shot is the third Covid-19 vaccine to be given the green light by the EMA, after ones made by Pfizer and Moderna.
Those were authorised for all adults and trials showed they provided more protection, with roughly 95% efficacy rates.
Two more vaccine makers also recently announced results, with Novavax saying this week that its shot appears 89% effective based on early findings and Johnson & Johnson saying its long-awaited single-shot vaccine was 66% effective at preventing moderate to severe illness.
Also today, the European Commission introduced measures to tighten rules on the exports of shots produced in the 27 EU countries.
The "vaccine export transparency mechanism" will be used until the end of March to control vaccine shipments to non-EU countries and to ensure that any exporting company based in the EU first submits its plans to national authorities.
The EU insisted the measure is not an export ban.
Officials said it is intended to ensure member nations get the shots they bought from vaccine producers.
They said the mechanism would not affect humanitarian deliveries and shipments to countries covered by the COVAX initiative co-led by the World Health Organisation.
The European Union and AstraZeneca also agreed today to make public a heavily redacted version of their coronavirus vaccine agreement.
Read more: 300,000 fewer doses of Covid-19 jab to be delivered to Republic by end of March
