BRUSSELS (REUTERS) - The European Union has struck a deal for up to 160 million doses of US firm Moderna's Covid-19 vaccine candidate, the head of the European Commission said on Tuesday (Nov 24), taking the EU's potential stock of Covid-19 shots to nearly two billion.

Last week, Moderna said its experimental vaccine was 94.5 per cent effective in preventing Covid-19, based on interim data from a late-stage clinical trial.

"I am happy to announce that tomorrow, we will approve a new contract to secure another Covid-19 vaccine," Dr Ursula von der Leyen said, adding the deal "allows us to buy up to 160 million doses of a vaccine produced by Moderna".

Actual purchases will be carried out by EU governments if the vaccine is approved by the EU's drug regulator.

The delivery timeline is unknown. The doses would be enough to vaccinate 80 million people, as the vaccine is expected to be administered in two doses.

In August, the EU's executive Commission, which co-leads talks with vaccine makers on behalf of member states, said it had held preliminary talks with Moderna over a deal for 80 million doses and an option for 80 million more.

The terms of the contract have not been disclosed.

An EU official involved in the talks told Reuters last week the EU was seeking a price below US$25 (S$34) per dose for Moderna's vaccine.

But Moderna chief executive Stephane Bancel said on Sunday that the company would charge governments between US$25 and US$37 per dose, depending on the amount ordered.

A spokesman for the Commission declined to comment on pricing.

It is the sixth supply deal the EU has negotiated with Covid-19 vaccine makers and takes the total number of doses secured by the bloc to 1.96 billion for its population of around 450 million.

Brussels has already struck deals with AstraZeneca, Pfizer-BioNTech, Sanofi-GSK, Johnson & Johnson and CureVac.

It is also in talks to buy US firm Novavax's potential Covid-19 vaccine.