Meanwhile, Ursula Von der Leyen, speaking to the European University Institute in Florence, said the EU was ready to discuss any proposals that address the crisis "in an effective and pragmatic manner.
"That's why we are ready to discuss how the U.S. proposal for a waiver on intellectual property protections for COVID-19 vaccines could help achieve that objective."
But drugmakers - who have produced coronavirus vaccines in record time - said the proposal could have the opposite effect, by disrupting a stretched and fragile supply chain.
Also of interest is that Germany, the EU's biggest economic power and home to a large pharmaceutical sector, rejected the idea, saying the reasons for the lack of vaccines were capacity and quality standards.
French President Emmanuel Macron said he was "very much in favour" of opening up intellectual property. However, a French government official said the lack of vaccines was the result of a lack of production capacity and ingredients, not of patents. "I would remind you that it is the United States that has not exported a single dose to other countries, and is now talking about lifting the patents," the official said.