Pharmaceutical company BioNTech and its U.S. partner Pfizer say they will provide 100 million more doses of their coronavirus vaccine to the European Union (EU) this year.

The two companies said Monday that the 27-nation group’s executive Commission exercised an option to purchase the additional doses, bringing the total number of shots to be delivered to the EU in 2021 to 600 million.

The announcement offers a much-needed boost to the EU’s sluggish and much-criticized vaccine rollout.

Sean Marett, the chief business officer of BioNTech, said deliveries of the company’s mRNA-based vaccine this year will cover two-thirds of the EU population.

The bloc has so far administered about 105 million shots to its population of some 450 million. Most vaccines require two shots to provide full immunization.