The European Union has agreed to buy at least 300 million doses of AstraZeneca’s potential COVID-19 vaccine in its first such advance purchase deal.

This could weaken plans led by the World Health Organisation for a global approach, Reuters reports.

The European Commission, which is negotiating on behalf of all 27 EU member states, said the deal included an option to purchase 100 million additional doses from the British drugmaker should its vaccine prove safe and effective.

The EU’s bilateral deal mirrors moves by the United States and other wealthy states, some of which are critical of the WHO’s initiative, and further reduces the potentially available stock in the race to secure effective COVID-19 vaccines.