Pfizer and BioNTech said Wednesday they have reached an agreement to supply the European Union with another 200 million doses of their Covid-19 vaccine.

The U.S. and German companies said in a statement that the doses come on top of the 300 million initially ordered. The EU’s executive Commission has an option to request a further 100 million doses.

They said the 200 million doses are expected to be delivered this year, with an estimated 75 million of them in the second quarter.

The Pfizer-BioNTech vaccine was the first of three so far to be approved for use in the EU, which faces criticism for a slow start to its vaccination campaign. The other two approved vaccines are from Moderna and AstraZeneca.