Europe's drug regulator will not set a minimum level of efficacy for potential Covid-19 vaccines when considering them for approval, it said on Wednesday, taking a different approach to that of its US counterpart.
Human studies need to demonstrate a convincing level of efficacy, but whether a shot would be considered acceptable for approval will be assessed case by case based on all available data on its safety and efficacy, the European Medicines Agency (EMA) said in an email.
"Therefore it is not possible to specifically quantify in advance the minimum level of efficacy for a vaccine to be considered acceptable for approval," it said.
The US Food and Drug Administration has said vaccines must demonstrate at least 50% efficacy - meaning at least twice as many infections among volunteers who got a placebo as among those in the vaccine group.
The EMA is reviewing candidate vaccines by drugmakers Pfizer, AstraZeneca and Moderna under a real-time release process, in an effort to speed up the approval if trials of any of those vaccines are successful. They are undergoing late-stage trials.
The EMA said on Wednesday its human medicines committee (CHMP) is drawing up guidance on its requirements for Covid-19 vaccine approval and will publish the information as soon as it is ready.