WASHINGTON, Feb.18 (CNA)- The Biden administration will pledge US$4 billion to a coronavirus vaccination programme for poorer countries in hopes of prying loose bigger donations from other governments, US officials said on Thursday (Feb 18).

US President Joe Biden will use his first meeting with leaders of Group of Seven advanced economies on Friday to announce an immediate US$2 billion donation to the COVAX programme co-led by the World Health Organization (WHO), officials said. COVAX aims to ensure a fair supply of coronavirus vaccines around the world.

The US will provide the remaining US$2 billion over the next two years as other nations fulfill and make their own pledges, the officials said.

"We want to turn this into a way to translate US$2 billion into several billion dollars, up to at least US$15 billion," said one of the officials, estimating the total amount needed for the global vaccination drive.

The US funding has already been approved by Congress.

COVAX aims to deliver at least 2 billion vaccine doses by the end of 2021 to cover 20 per cent of the most vulnerable people in poor and middle-income countries. The programme is at risk of failing, mainly due to a lack of funds.

The head of the Gavi vaccine alliance, which co-leads the programme, has also said COVAX needs greater political support, as wealthier nations strike fresh deals with developers to secure limited supplies.

The incoming head of the World Trade Organization and others have underscored the urgent need to jump-start vaccinations across Africa and in other regions that are lagging behind.