The White House Thursday said the United States would resume its funding for the World Health Organization (WHO), while also launching a $1.9-trillion plan to tackle the COVID-19 pandemic spiraling out of control in the country, as President Joe Biden plans to uphold his election campaign promises.

On his first day on the job, Biden confirmed he had reversed the decision of former president Donald Trump to quit the WHO.

"Under trying circumstances, this organization has rallied the scientific and research and development community to accelerate vaccines, therapies and diagnostics," top U.S. scientist Anthony Fauci told a WHO meeting via video-link, confirming that the U.S. would continue to pay its dues to the organization.

Biden was a fierce critic of Trump's approach to tackling the virus in the U.S., which with more than 400,000 people dead is the world's worst-hit nation.

The new president is seeking to vaccinate 100 million people in the next 100 days, increase the use of masks and testing, expand the public health workforce and offer more emergency relief to those struggling with the restrictions.

"For almost a year now, Americans could not look to the federal government for any strategy," said Jeff Zients, coordinator of the new COVID-19 task force. "As president Biden steps into office today, that all changes."

Virus cases are approaching 100 million globally, with more than 2 million deaths and many millions – from Beijing to Berlin – still living under lockdowns, curfews or other restrictions.

Europe has been particularly hard hit, though the Russian capital Moscow announced Thursday it was lifting many of its harshest restrictions as Mayor Sergei Sobyanin expressed "cautious optimism" over the current figures.

'War zone'

More contagious coronavirus variants have traveled quickly around the globe, tempering optimism that mass vaccination campaigns would bring a swift end to the worst phase of the pandemic.

And the WHO has repeatedly warned that richer countries are hogging the vaccine, a point underscored by data from Africa suggesting the second wave is proving far deadlier than the first.

John Nkengasong of Africa Centers for Disease Control and Prevention said more infections meant more pressures on ill-equipped health systems, adding: "That also means you're overwhelming the ability of nurses, doctors to manage patients."

However, the U.S. provided a boost to efforts to share out vaccines across the world by announcing it intended to join the Covax initiative, a pool of doses supplied by countries and companies.

Germany meanwhile confirmed it was willing to help Russia to develop its Sputnik vaccine – which has been rolled out by Moscow despite still being in clinical trials.

And early results from studies of the Pfizer-BioNTech vaccine suggested it would be effective against the British variant, which is fueling a surge that has overwhelmed U.K. hospitals.

"When you go into a hospital... in some cases it looks like a war zone," said the British government's chief scientist, Patrick Vallance.

'Auspicious' rollout

Britain is facing record daily death tolls and has rammed through the approval of several vaccines, betting heavily on the jabs as an ultimate solution to the contagion.

But the same urgency is not being felt everywhere.

The Himalayan kingdom of Bhutan plans to vaccinate its entire population, but not until after March 13 because the period before has been deemed "inauspicious."

The shots will start after that, the prime minister's office said, adding that it was "important we roll out the nationwide vaccination on an auspicious date."

In Japan, however, time is of the essence. With six months to go until the Tokyo Olympic Games, questions are intensifying over the viability of holding a tournament that will require thousands of athletes to fly in around the world.

Olympic chief Thomas Bach said there was "no reason whatsoever" to believe the games would not go ahead, adding: "This is why there is no plan B and this is why we are fully committed to make these games safe and successful."

While sports officials grapple with scheduling headaches and event cancellations, some politicians have had their reputations trashed by the virus.

Mongolia's Prime Minister Khurelsukh Ukhnaa quit Thursday after protests prompted by the treatment of a coronavirus patient and her newborn baby.

TV footage showed the woman being moved to an infectious disease center wearing only hospital pajamas and plastic slippers, despite temperatures of minus 25 degrees Celsius (minus 13 degrees Fahrenheit).

"As a prime minister, I must take the responsibility," Khurelsukh said, describing the footage as "heartbreaking."