Updated at 2:15 p.m. ET
The European Union will soon start administering AstraZeneca's COVID-19 vaccine — the third vaccine it has endorsed. The European Commission gave conditional authorization to the vaccine on Friday, hours after regulators recommended the move.
The European Medicines Agency said the AstraZeneca vaccine will prevent the deadly coronavirus from affecting people who are at least 18 years old. The vaccine has been administered in the U.K. since early this month.
"I expect the company to deliver the 400 million doses as agreed," European Commission President Ursula von der Leyen said.
The new vaccine joins the Moderna and Pfizer-BioNTech vaccines that are already authorized in the bloc. It could also help address supply shortages that have hindered Europe's vaccination campaigns.
The vaccines "will all help to bring the pandemic under control and protect the citizens of the EU," EMA Executive Director Emer Cooke said in a video briefing about her agency's recommendation.
The AstraZeneca vaccine, which was developed with the University of Oxford, requires two doses, from four to 12 weeks apart. In clinical trials, it showed around 60% efficacy in protecting people from SARS-CoV-2, the virus that causes COVID-19, according to the European Medicines Agency.
"The evaluation of overall safety and efficacy was based on clinical studies that included 24,000 people," said Bruno Sepodes, the agency's vice chair, referring to trials in the U.K., Brazil and South Africa.
"We will also soon receive additional data coming from a study currently ongoing in the U.S.," Sepodes added.
The AstraZeneca vaccine works by modifying another virus, from the adenovirus family, to include the gene for making the SARS-CoV-2's spike proteins — the crown-like studs the coronavirus uses to breach cells and cause disease. After the vaccine is injected, cells use the gene to make the spike protein, which then triggers the immune system to provide protection from the coronavirus.
Because most of the people in the clinical studies are between 18 and 55, there has been speculation that the EU might set a maximum age of 55 for people receiving the vaccine.
The European Medicines Agency acknowledged the lack of data about how people over 55 are protected by and tolerate the vaccine. But it added, "However, protection is expected, given that an immune response is seen in this age group and based on experience with other vaccines."
The agency plans to analyze more information as it arrives from further studies.
The EU and AstraZeneca have recently been sparring over the number of doses the bloc would get after the company warned it would not send as much vaccine as it initially promised. Von der Leyen responded by saying that the EU is spending billions on vaccines and expects pharmaceutical companies to hold up their end of the deal.
Despite the reduction, AstraZeneca said earlier this week it still expects to send "tens of millions of doses in February and March to the European Union, as we continue to ramp up production volumes."