MADRID, Jan. 31 (Xinhua) -- European scientists call for closer global vaccine cooperation as the European Union (EU) suffers from COVID-19 vaccine supply shortages.

The European Commission granted conditional marketing authorization for the COVID-19 vaccine developed by British company AstraZeneca and Oxford University on Friday, although the bloc seems unlikely to get the amount of doses as agreed for the moment.

The EU has been squabbling with the British company over the latter's announcement that it may deliver considerably fewer doses than promised for the first quarter. The bloc published the contract with AstraZeneca on Friday, and meanwhile launched a transparency measure to regulate vaccines export from the union.

European leaders on Tuesday called for more multilateral cooperation, free trade and the fair distribution of COVID-19 vaccines on the second day of the virtual World Economic Forum Davos Agenda as solutions to the COVID crisis.

Vaccine rollout in the 27-nation bloc has been criticized as being slow compared to other developed regions as the European Union (EU) is struggling to overcome the pandemic that has already killed more than 2.1 million people worldwide.