Enlarge / President Joe Biden speaks to a member of the media after delivering remarks in the East Room of the White House with Vice President Kamala Harris, left, in Washington, DC, on Monday, May 17, 2021. Biden plans to send an additional 20 million doses of vaccines abroad by the end of June. (credit: Getty | Bloomberg )

President Joe Biden announced on Monday that the United States will share at least 20 million doses of Pfizer-BioNTech, Moderna, and Johnson & Johnson COVID-19 vaccines with other countries over the next six weeks.

The pledged doses will be in addition to 60 million stockpiled doses of AstraZeneca’s vaccine the administration has previously said it will donate after they’re cleared by the Food and Drug Administration.

The announcement comes amid mounting pressure for the US and other rich nations to share doses with low- and middle-income countries, some of which are struggling with COVID-19 surges amid a dearth of doses. It also comes as the US has a glut of vaccine doses and is now struggling to convince a vaccine-hesitant portion of the population to take the available shots.

Enlarge / Chinese President Xi Jinping learns about the progress on a COVID-19 vaccine during his visit to the Academy of Military Medical Sciences in Beijing on March 2, 2020. (credit: Getty | Xinhua News Agency )

China has now signed onto a massive, global alliance to develop and equitably distribute a coronavirus vaccine—putting the United States’ absence from the pact into yet sharper relief.

With its late entry announced Friday, China joins at around 170 other countries in the pact, called the COVAX Facility . The effort is being spearheaded by the World Health Organization and co-led along with the Coalition for Epidemic Preparedness Innovations (CEPI) and Gavi, the Vaccine Alliance.

COVAX is designed to pool resources to help develop a vaccine and bring it to market globally. Once at that point, the alliance will help ensure all participating countries have access to whichever vaccine candidate(s) prove successful, regardless of where it was developed. It will also provide financial assistance to lower income countries to access the vaccine. So far, at least 77 high-income countries (including China) have signed on, as well as 92 low- and middle-income countries.

Enlarge / World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus attends a press conference organized by the Geneva Association of United Nations Correspondents (ACANU) amid the COVID-19 outbreak, caused by the novel coronavirus, on July 3, 2020 at the WHO headquarters in Geneva. (credit: Getty | Fabrice Cof )

A total of 156 countries—representing about 64 percent of the world’s population —have committed to pooling resources to help develop, buy, and equitably distribute two billion doses of a COVID-19 vaccine by the end of 2021.

“This isn’t just the right thing to do, it’s the smart thing to do,” said Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, which is co-leading the effort along with the Coalition for Epidemic Preparedness Innovations (CEPI) and Gavi, the Vaccine Alliance.

So far, 64 high-income countries have signed on to the effort, as well as 92 low- and middle-income countries , which would be eligible for support in procuring vaccine doses. Gavi CEO Seth Berkley said in a WHO press conference on Monday that he expects 38 more countries to sign up in the coming days.