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US President Joe Biden plans to call for a global vaccine supply meeting at the UN General Assembly this month, sources say, as wealthy nations face pressure to provide more shots for developing countries.
Mr Biden intends to host a session during the UN meetings, although its scope and those who would attend are not yet clear.
While the US has been contacting other countries to take part, it has not finalised its plans, the sources said.
Mr Biden has praised the American record on shipments, while previous attempts to encourage widespread donations have had mixed results.
The US has pledged to donate more than 600 million doses globally by the end of June 2022, and has shipped 140 million so far, although advocates say that is not enough.
Billions of doses are needed to vaccinate the world and slow the spread of the coronavirus and the development of more dangerous variants.
Mr Biden’s administration is still planning his schedule around the UN meetings, a senior administration official said.
The US is interested in events related to public health and the pandemic, and expects opportunities for him to speak with other world leaders about it then, the official said.
The White House declined to comment on whether Mr Biden would propose the gathering, which was reported earlier by The Washington Post.
The Group of Seven wealthy nations announced a push in June to donate one billion new doses, although it ultimately pledged only 613 million, including 500 million from the US.
Covax, the global vaccine-sharing programme, slashed its supply forecast this week, saying it would receive 1.4 billion doses by the end of the year, instead of the 1.9 billion it expected as of June.
Lawrence Gostin, a Georgetown law professor and director of the World Health Organisation Collaborating Centre on Public Health Law and Human Rights, called on wealthy nations to pledge donations of as many as 10 billion doses in six months.
Mr Gostin asked Mr Biden to do more to transfer vaccine technology and licences to developing nations so that they can begin their own production, although that process is time-consuming.
“If we’re going to meet this moment, this once-in-a-century moment, we have to do what we’ve never dreamed before,” he said.
Mr Gostin urged Mr Biden to focus on production of messenger-RNA vaccines because it was easier to increase their production, and said he was disappointed with the G7 pledge.
“I was totally underwhelmed by the G7 announcement," he said. "It didn’t make a dent. The inequities have not gotten better.”
Wealthy countries are beginning to introduce booster shots that will further eat into supply.
Dr Tedros Adhanom Ghebreyesus, the World Health Organisation’s director general, on Wednesday called for a moratorium on boosters until at least the end of the year.
Dr Tedros said that drug makers giving priority to deals with richer nations had left low-income countries “deprived of the tools to protect their people".