Happy to be proved wrong though.
It would be shooting itself in the foot to admit the vaccines it had bought in a group-buy scheme were ineffective or in any way sub-standard. Member states would be furious, and Ursula would have been gone.
This article has a summary of statements from different politicians - https://news.sky.com/story/covid-19-what-eu-leaders-said-abo... The closest I can see for the EC is one from Ursula, with the article reporting:
"She then suggested the UK had compromised on "safety and efficacy" by approving the jab so early, despite the EMA reaching the same conclusions as the UK's internationally-respected MHRA which approved the vaccine."
(That is realistically just her attempts to excuse a slower approval process that ultimately reached exactly the same outcome)
Possibly worse situation in Germany where blatent misinformation was published regarding the Oxford vaccine. Consider the gravity of this given Germany's population is far more "anti-vac" than say the UK.
The EU and Germany/France in particular did a stellar job of destroying the Oxford vaccine's credibility.