GENEVA (Reuters) - The United States under President Joe Biden intends to join the COVAX vaccine facility that aims to deliver coronavirus vaccines to poor countries, his chief medical adviser, Anthony Fauci, told the World Health Organization (WHO) on Thursday.

Fauci, speaking to the WHO executive board, confirmed that the United States would remain a member of the U.N. agency and said it would work multilaterally on issues from the COVID-19 pandemic to HIV/AIDS.

“This is a good day for WHO and a good day for global health,” WHO director-general Tedros Adhanom Ghebreyesus said.

“WHO is a family of nations and we are all glad that the U.S. is staying in the family,” Tedros said.

Austria, speaking for the European Union, Britain, Canada, Kenya and South Korea also welcomed the U.S. turnabout and pledged to work together to strengthen multilateral cooperation.

Fauci, speaking from Washington a day after Biden was inaugurated, said: “President Biden will issue a directive later today which will include the intent of the United States to join COVAX and support the ACT-Accelerator to advance multilateral efforts for COVID-19 vaccine, therapeutic, and diagnostic distribution, equitable access, and research and development.”

The first batches of coronavirus vaccines are expected to go to poorer countries in February under the COVAX scheme run by the WHO and the GAVI vaccine alliance, WHO officials said this week, while raising concerns that richer countries are still grabbing the lion’s share of available shots.

“”We welcome the decision by the United States to join the COVAX facility, because vaccinating our own populations is not enough scientifically or morally,” Britain’s ambassador, Julian Braithwaite, told the board.

“We need a global vaccination campaign if we are to overcome this global pandemic.”

Austrian ambassador Elisabeth Tichy-Fisslberger said on behalf of the EU: “It is time to renew joint EU-US efforts aimed at strengthening as well as reforming international organisations such as the World Health Organization.”

The United States will “fulfil its financial obligations” to WHO, Fauci said, adding it would work with the other 193 member states on reforms.

Biden’s predecessor, Donald Trump, halted funding to the WHO, where the United States is the largest donor, and announced a process to withdraw in July 2021 in what was seen as part of a broader U.S. retreat from multilateral organizations.

Trump accused the WHO of being “China-centric” in the initial stages of the outbreak, a charge rejected by Tedros.

Fauci said it was important to have transparency about the early days of the pandemic to prepare for future events.

Regarding a WHO-led mission investigating the origins of the SARS-CoV-2 virus, currently in the central city of Wuhan, where the first cases were detected in December 2019, he said: “The international investigation should be robust and clear, and we look forward to evaluating it.”