The humanitarian group Doctors Without Borders unveiled a new report Monday estimating that the United States is hoarding nearly 500 million excess coronavirus vaccine doses—the most of any country—as poor nations across the globe remain without sufficient access to lifesaving shots.

“It’s reckless and dangerous for the U.S. and other high-income countries to be sitting on excessive stocks of Covid-19 vaccines while others… are desperate to provide their most vulnerable people with even their first dose,” Dr. Carrie Teicher, director of programs at Doctors Without Borders USA, said in a statement, arguing that the Biden administration’s hoarding of doses calls into question “its claim to be a global leader on Covid-19.”

“The longer people everywhere remain unprotected, the more lives will be lost and the more likely it is that new and potentially deadlier variants will take hold,” said Teicher. “The U.S. must immediately make public and concrete commitments to redistribute excess Covid-19 vaccines globally if it truly wants to end this pandemic.”

To date, the Biden administration has pledged to donate roughly 1.1 billion surplus coronavirus vaccine doses to low-income countries, a commitment that public health campaigners have criticized as badly inadequate to meet global needs. According to the State Department, the U.S. has shipped around 177 million vaccine donations thus far.

The World Health Organization has estimated that in order to vaccinate at least 70% of the global population by next year, 11 billion doses—equitably distributed—will be necessary.

Doctors Without Borders—known internationally as Médecins Sans Frontières (MSF)—said Monday that “even while factoring in third-dose boosters for high-risk groups, high-income countries are hoarding an estimated 870 million excess doses,” including the nearly 500 million in the U.S. alone.

“The rapid redistribution of these doses to low- and middle-income countries could save nearly one million lives by mid-2022,” the group said. “In addition to immediately redistributing vaccine doses globally and demanding Pfizer-BioNTech and Moderna share Covid-19 mRNA vaccine technology, the U.S. must remain committed and urge all countries to support the ‘TRIPS waiver’ proposal at the World Trade Organization to waive intellectual property monopolies on all Covid-19 products during the pandemic.”

Last week, the U.S. surpassed 400 million coronavirus vaccine doses administered—a milestone that the Biden White House readily touted. But as Public Citizen president Robert Weissman noted in a statement Friday, “All African countries combined have had roughly 150 million doses administered.”

“Africa has a population over 1.34 billion. The U.S. population is 330 million,” Weissman said. “Put simply: Africa has four times the population of the U.S. but has administered about one-third the number of Covid vaccine doses… This unconscionable vaccine apartheid is not just leaving billions of people in African and other developing countries vulnerable to preventable disease, suffering, and death, it is dramatically increasing global poverty rates—as well as the death, disease, and hunger that accompanies severe poverty.”

In its report on Monday, Doctors Without Borders warned that “millions of doses could be tragically wasted if HICs [high-income countries] do not immediately redistribute excess doses.”

“G7 and E.U. countries alone could waste 241 million doses by the end of 2021,” the group estimated. “Still, pharmaceutical companies continue to prioritize high-profit sales to HICs over a fairer distribution of vaccines.”

As the New York Times reported over the weekend, the U.S.-based pharmaceutical giant Moderna “has been supplying its shots almost exclusively to wealthy nations, keeping poorer countries waiting and earning billions in profit.” Moderna’s profits during the global coronavirus pandemic propelled two of its co-founders and one early investor to the Forbes 400 list of the richest people in the U.S.

“After developing a breakthrough vaccine with the financial and scientific support of the U.S. government, Moderna has shipped a greater share of its doses to wealthy countries than any other vaccine manufacturer,” the Times noted, citing the data firm Airfinity. “Scientists at the National Institutes of Health worked with the company to develop the vaccine. The United States kicked in $1.3 billion for clinical trials and other research. And in August 2020, the government agreed to preorder $1.5 billion of the vaccine, guaranteeing that Moderna would have a market for what was an unproven product.”

The Times report intensified pressure on the Biden administration to use the U.S. government’s ownership of a key patent as leverage to force Moderna to share its vaccine recipe with the rest of the world.

“It’s not news that a pharmaceutical company puts profits first. That is what companies do,” tweeted Amy Maxmen, a reporter at Nature. “The onus is on the U.S. government to put lives over profits, particularly when they give companies massive handouts.”

Teicher of Doctors Without Borders said Monday that “the Covid-19 vaccine inequity that pharma has created by putting profits before people’s health is nothing short of shameful.”

“In addition to developing a concrete dose redistribution timeline by the end of October, the U.S. government must demand that Pfizer-BioNTech and Moderna share mRNA vaccine technology and know-how with other manufacturers,” Teicher added. “Sharing mRNA technologies will increase the global production and supply of Covid-19 vaccines, saving lives in this pandemic and in the future.”