Prime Minister Boris Johnson on Friday plans to announce that the U.K. will donate surplus coronavirus vaccines to developing countries, joining a similar commitment by President Emmanuel Macron to boost the global battle against the Covid-19 pandemic.

The “majority” of any future U.K. surplus coronavirus vaccines will be shared with the World Health Organization-backed Covax program, Johnson’s office said late Thursday in a statement. That’s on top of the 548 million pounds ($766 million) the country has already donated to the program, which is aimed at supplying some of the world’s poorest nations with inoculations.

Coming ahead of a Friday video call among the leaders of the Group of Seven nations hosted by Johnson, momentum may be building toward a coordinated effort that’s been absent to date on the part of the world’s advanced economies to address the pandemic, especially among countries least equipped to cope.

Macron has committed to sending 5% of France’s secured Covid-19 vaccine supplies to poorer countries through the Covax program, and Johnson plans to encourage fellow leaders to increase their funding.

The French president has called on the U.S. and Europe to back his proposal to share 4% to 5% of their coronavirus vaccine supplies, and in an interview with the Financial Times, said that German Chancellor Angela Merkel supports the idea. Johnson’s office didn’t say how many doses the U.K.’s prepared to contribute from its stock.

U.S. Support

U.S. officials, speaking to journalists on condition of anonymity ahead of the call, said that President Joe Biden would announce a total of $4 billion in funding for COVAX but that the country did not plan to share any of its doses with other nations until its domestic vaccination needs were met.

The U.K. prime minister also plans to call on his counterparts to back efforts to speed up the development of vaccines for new diseases, setting a target of slashing the period to 100 days from the approximately 300 days it took to develop coronavirus vaccines.

The U.K. has already secured more than 400 million doses from seven manufacturers to vaccinate its population of 67 million people. An assessment will be made later in the year to determine what can be donated to Covax, based on supply chain reliability and whether new vaccines are needed to tackle variants or as booster doses in the fall.