President Joe Biden at the meeting - his first multilateral engagement since taking office - will announce the U.S.is directing $4 billion Congress allocated to Gavi in December to help procure coronavirus vaccines for poor countries, the senior official said.
It is the first United States contribution to the scheme, which was snubbed by President Donald Trump.
In addition to Friday's pledge, Biden will deliver a virtual address to the Munich Security Conference and travel to Pfizer's vaccine manufacturing facility in the USA state of MI.
Trump had terminated U.S. funding for the WHO - as its biggest contributor - in the middle of the deadliest pandemic to hit the world in more than 100 years.
Administration officials characterized the decision as one meant to prevent further spread and mutation of the virus, which disregards borders and the relative income levels of different countries.
J&J said an emergency use listing is a prerequisite for supplying vaccines to the COVID-19 Vaccines Global Access Facility (COVAX) programme, co-led by World Health Organization, which aims to deliver doses to poor and middle-income countries.
That "unprecedented acceleration of global inequality" was paving the way for "a war of influence over vaccines", Macron said, and playing into the hands of Russian Federation and China, which are exporting state-funded vaccines around the world. He will be encouraging G7 leaders to increase their funding for COVAX in support of equitable access to vaccines. "And we also know the more disease that's out there, the more likely we are to see variants".
The COVAX program has already missed its own goal of beginning coronavirus vaccinations in poor countries at the same time that shots were rolled out in rich countries.
COVAX aims to ensure a fair supply of coronavirus vaccines around the world. World Health Organization says COVAX needs $5 billion in 2021. The Biden administration official on a Thursday background call made clear the priority is vaccinating Americans.
"This pledge to COVAX does not impact the vaccination program in the United States at all", an official said.
The Liberals have been under fire from worldwide organizations and some opposition parties for the decision to accept 1.9 million doses of vaccine from COVAX for domestic use in Canada by the end of June. It has also purchased doses of the still-to-be-authorized Johnson & Johnson product, as well as other vaccines still in development. However, the details on when and how many doses may be donated remain vague.
Asked about Macron's comments and the timeline on donations, another official said, "There are a lot of options on the table, but I don't think we should get locked down in what we might do once the USA population is vaccinated".
India is the largest beneficiary of Covax, clinching a deal earlier this month to receive 97.1 million of the 2 billion doses to be distributed under the programme, according to an agreement announced earlier in February. As leaders of the G7 we must say today: "never again", he added.
The other side: The White House said on Thursday's briefing call that the administration planned to turn to donations only after all US demand was met.
"Certainly we've seen attempts by other countries - China and Russian Federation - to use vaccines as a means of making progress diplomatically", White House press secretary Jen Psaki said.
He has since vowed to return the USA to the world stage and reclaim its leadership role that was forsaken by Trump as he had sought to pursue an America-first agenda. "But we are - we watch those actions with concern".