ROME — From the opening moments of the Group of 20 summit on Saturday, the leaders of the world’s largest economies needed to ship a robust message about ending the coronavirus pandemic: Throughout an unconventional group {photograph}, they had been joined on the dais by docs in white coats and first responders from the Italian Crimson Cross.

In his remarks opening the assembly — the primary gathering in individual for the group because the pandemic struck — Prime Minister Mario Draghi of Italy pointed to the stark disparity in entry to vaccines between richer and poorer nations.

“Going it alone is solely not an possibility,” mentioned Mr. Draghi, whose nation is internet hosting the summit. Now, he added, the world may “lastly have a look at the longer term with nice — or with some — optimism.”

However because the leaders gathered to debate plans to guard towards future pandemics, well being consultants and activists expressed issues that the world’s richest nations had been nonetheless not doing sufficient to assist folks in poor nations survive the present one.

Advisers mentioned President Biden, who has promised to make the US an “arsenal of vaccines,” wouldn’t announce concrete plans associated to closing the hole between wealthy and poor nations on vaccination charges. A senior administration official mentioned Mr. Biden had met with a bunch of leaders early within the day and pushed them to help debt reduction and permit extra emergency financing to succeed in poor nations whose economies have been battered by the pandemic.

Whereas rich nations are providing folks third vaccine doses and more and more inoculating kids, poor nations have administered an estimated 4 doses per 100 folks, in line with the World Well being Group.

Mr. Biden mentioned in June that the US would purchase 500 million Pfizer-BioNTech coronavirus vaccine doses for poorer nations. He adopted up in September by saying a further 500 million Pfizer doses, together with the promise of a further $750 million for vaccine distribution, roughly half of it via a nonprofit concerned in international vaccinations.

Only about 300 million of these doses are anticipated to be shipped this 12 months, a quantity that consultants say falls in need of the quantity wanted for significant safety towards the virus.

However the president’s advisers mentioned he got here into the summit focused on a number of issues, together with fixing international provide chains, urging investments to curb local weather change, and assembly with the leaders of France, Britain and Germany to debate methods to return to a 2015 nuclear accord with Iran that the Trump administration scuttled.

Earlier than that assembly, Mr. Biden steered to reporters that talks to restart the accord had been “scheduled to renew.” However in a unexpectedly launched joint statement, the group appeared to place the brakes on the president’s assertion.

The assertion mentioned the leaders “welcome President Biden’s clearly demonstrated dedication to return the U.S. to full compliance” with the accord and “keep in full compliance, as long as Iran does.”

On Saturday, Mr. Biden and different world leaders endorsed a landmark global agreement that seeks to dam massive firms from shifting earnings and jobs throughout borders to keep away from taxes — a win for the president, whose administration pushed laborious to hold the deal over the end line.

The leaders had been set to formally again the accord in a communiqué to be launched on Sunday, an administration official mentioned.

However well being consultants and influential advocates, together with Pope Francis, have urged Mr. Biden throughout his journey to remain centered on closing the vaccine hole for poor nations, who’re significantly weak to the virus and its variants.

Jake Sullivan, the president’s nationwide safety adviser, advised reporters on Air Drive One en path to Rome that “the principle thrust of the trouble on Covid-19 isn’t truly touring via the G20.” He mentioned {that a} virtual summit that Mr. Biden convened in September had set “extra formidable targets” for nations to pledge to share doses of the vaccine.

Though Secretary of State Antony J. Blinken is scheduled to host a gathering of dozens of nations and nongovernmental organizations this 12 months to safe commitments on vaccine sharing, Mr. Sullivan mentioned the main focus for the Group of 20 was on the longer term.

“You actually have a failure of developed nations’ management post-Covid,” mentioned Célia Belin, a visiting international coverage fellow within the Middle on the US and Europe on the Brookings Establishment. “That is going to have penalties.”

Certainly, providing vaccine doses to creating nations is greater than an altruistic gesture on the a part of rich nations. The extra the virus continues to flow into globally, the extra probably it’s to proceed producing deadly variants, making it more durable to finish the pandemic and rendering weak wealthy and poor alike.

Since arriving in Rome, Mr. Biden has already heard a private attraction to do extra: Throughout a meeting at the Vatican on Friday, Pope Francis pushed the president on the difficulty, a senior official mentioned afterward.

And in an open letter to the Group of 20, the pinnacle of the World Well being Group, Dr. Tedros Adhanom Ghebreyesus, urged the leaders of the world’s largest economies “to assist stem the pandemic by increasing entry to vaccines and different instruments for the folks and locations the place these are in shortest provide.”

Because the summit acquired underway, it’s also drew a mélange of protesters — laid-off manufacturing facility employees, local weather activists, anti-globalization campaigners, unions, feminist teams, Communists and a few vaccine skeptics.

“There might be many people,” mentioned Gino Orsini, a consultant for the Si Cobas union, one of many organizers of an indication deliberate for Saturday to coincide with the gathering. The group is protesting what it says is the exploitation of employees by the worldwide elite.

This 12 months is the twentieth anniversary of the Group of 8 summit that Italy hosted in the northern city of Genoa that was marred by rioting. It’s also a second of rigidity between the authorities and opponents of the Italian authorities’s coronavirus vaccination necessities, which have resulted in violent clashes.

“The extent of consideration is most,” mentioned Giovanni Borrelli, a neighborhood authorities official, including that 5,500 further regulation enforcement officers had been being deployed this weekend.

Emma Bubola contributed reporting.