Following the summit, Biden, Johnson and European Union leaders in the G7 will join another gathering online, the annual Munich Security Conference, to discuss "renewing transatlantic cooperation".
Biden will become the first USA president to address the Munich meeting, underlining a decisive shift after cooperation was all but broken under his go-it-alone predecessor Donald Trump.
The head of the Gavi vaccine alliance, which co-leads the program, has also said Covax needs greater political support, as wealthier nations strike fresh deals with developers to secure limited supplies.
Leaders of the Group of Seven economic powers are holding their first meeting of 2021 on Friday, and vowing to share coronavirus vaccines with the world's poorest countries - though details of how soon and how much they will give remain scarce. Biden will also pledge an additional $2 billion in funding contingent on contributions from other nations and dose delivery targets being met.
Macron has expressed concern about a "war of influence over vaccines" by China and Russian Federation.
"This pandemic is not going to end unless we end it globally", a senior administration official said. "And we also know the more disease that's out there, the more likely we are to see variants".
The COVAX program to vaccinate the poorer countries around the world is expected to cost $15 billion worldwide, $4 billion of which will come from the US over the next few years, including $500 million right away, per the report.
It had fallen short of its funding targets, but the $2 billion offered by the USA will make up significant ground.
Joe Biden makes his presidential debut at the G7 on Friday as America's partners re-focus their collective heft on pandemic recovery and climate change after the psychodramas of the Trump era. The Biden administration official on a Thursday background call made clear the priority is vaccinating Americans.
The Biden administration said it expects to have enough vaccine doses for all Americans by the end of July, though it will take more time to complete vaccinations.
India has also recently begun donating and selling doses of vaccines produced domestically to poor countries that don't have access to other shots.
That is likely to mean the U.S. will have ample surplus doses that could be donated to poorer nations. The Biden administration is looking to develop a framework to donate excess vaccines "once there is a sufficient supply in the USA".
The timeline for what will depend on when there is a sufficient supply in the US.
Canada has pledged $220 million to COVAX and another $865 million to the ACT Accelerator, which tries to ensure low- and middle-income countries have equitable access to medical treatments during the pandemic.
"The virus won't wait on us to be ready before it mutates, so we need to get these vaccines around the world as quickly as possible", said Romilly Greenhill, U.K. director of anti-poverty group the One Campaign.
The Prime Minister has also confirmed today that the United Kingdom will share the majority of any future surplus coronavirus vaccines from our supply with the COVAX procurement pool to support developing countries, in addition to the UK's £548 million funding for the scheme.
But Biden, who announced last week that the USA will have enough supply of the vaccine by the end of the summer to inoculate 300 million people, remains focused for now on making sure every American is inoculated, administration officials say. "You know, the President is engaged with a range of leaders around the world, conveying how he wants to return the United States to have a central seat on the world stage, and we're working to do that through a range of actions".