The European Union tightened its vaccine export control mechanism on Wednesday to prevent what it sees as an unfair one-way flow of vaccines out of the bloc.

A Pfizer employee is at work at packaging line of the factory of US multinational pharmaceutical company Pfizer in Puurs on February 22, 2021. (File photo: AFP)

The measure could limit vaccine exports to countries like Britain which produce some of their own vaccines but do not in turn send doses to the EU.

"Accordingly, we today adopted two adjustments to the existing mechanism," European Commission Vice President Valdis Dombrovskis said.