ROME: The European Union is in talks with Pfizer and BioNTech over ordering up to 100 million more doses of their COVID-19 vaccine, three sources close to the matter said on Tuesday, as European governments battle to speed up immunisations.

The bloc, with a population of 450 million, has already ordered 200 million doses of the Pfizer-BioNTech vaccine and has taken up an option to buy another 100 million under a contract signed with the two companies in November. Each recipient needs two doses of the vaccine.

The sources said the EU is seeking to buy 50 or 100 million additional doses from the companies.

The new doses could be delivered as soon as in the third quarter, two sources said. But one of the sources added that deliveries could also be made in the fourth quarter and would be at the same price per dose as agreed in the existing contract.

The EU agreed to pay 15.5 euros per dose in that contract, according to an EU document seen by Reuters.

An European Commission spokesman declined to comment on Tuesday on numbers of possible orders. But on Monday he told a news conference the EU was trying to secure more doses from Pfizer and BioNTech in addition to the 300 million shots already booked

A Pfizer spokesman said he could not comment as discussions with governments are confidential. BioNTech did not want to comment.