BERLIN, April 9 (Reuters) - The European Union will shortly sign contracts to purchase up to 1.8 billion doses of coronavirus vaccine to cover the bloc's need for booster shots over the coming two years, German daily Die Welt reported on Friday.

The newspaper said that contracts would be signed for deliveries of 900 million doses, with further contracts creating an option for another 900 million doses to be bought. The planned purchases would also cover the 70-80 million children in the EU, who are not currently being vaccinated.

The planned orders will be for so-called mRNA vaccines, with a preference for manufacturers who are EU-based or who have production facilities in Europe.

Only the Biontech/Pfizer vaccine, which is manufactured in Belgium and Germany, and Moderna, which manufactures in Spain and Switzerland, currently meet these requirements. (Reporting by Thomas Escritt; Editing by Maria Sheahan)