In his first full day as US president, Joe Biden tackled his country's staggering coronavirus caseload with a spate of new measures, including mask-wearing and quarantining requirements, as EU leaders "strongly discouraged" their constituents from non-essential travel.

Before signing 10 executive orders to strengthen the US fight against Covid, Biden confirmed earlier in the day that he had reversed his predecessor Donald Trump's decision to quit the World Health Organization (WHO).

The new "first family" of the United States pose in front of a statue of Abraham Lincoln while wearing face masks following Joe Biden's inauguration The new "first family" of the United States pose in front of a statue of Abraham Lincoln while wearing face masks following Joe Biden's inauguration Photo: POOL / JOSHUA ROBERTS

Under the new measures, travelers to the US, in addition to needing a negative Covid test result before flying, will now need to quarantine upon arrival, Biden said. This toughened existing regulations under Trump.

Biden's other orders included reenergizing a so-far-stumbling vaccination program and expanding requirements to wear masks on public transport.

Graphic highlighting the countries with the largest number of COVID-19 cases and deaths in the past week. Graphic highlighting the countries with the largest number of COVID-19 cases and deaths in the past week. Photo: AFP / John SAEKI

The longtime politician was a fierce critic of Trump's approach to handling the virus in the US, 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 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.

On Thursday alone the US registered 4,045 new deaths and more than 192,000 new cases over the past 24 hours.

Paramedics take a man showing symptoms of COVID-19 to hospital near Pretoria in South Africa. A new strain of the virus that emerged in the country is already spreading around the world Paramedics take a man showing symptoms of COVID-19 to hospital near Pretoria in South Africa. A new strain of the virus that emerged in the country is already spreading around the world Photo: AFP / Phill Magakoe

With infection rates spiraling and vaccine campaigns still in their infancy -- and with the global death toll now past two million -- countries from Lebanon to Sierra Leone are tightening restrictions.

EU Commission chief Ursula von der Leyen and Council president Charles Michel encouraged Europeans to refrain from non-essential travel Thursday while warning that tougher restrictions on movement could come within days if efforts to curb the coronavirus fall short.

A temporary vaccination centre has been set up inside Salisbury Cathedral in southwest England, with musicians playing the 19th-century organ to soothe the nerves of those waiting for their shots A temporary vaccination centre has been set up inside Salisbury Cathedral in southwest England, with musicians playing the 19th-century organ to soothe the nerves of those waiting for their shots Photo: AFP / JUSTIN TALLIS

After a four-hour summit by video link with the heads of government of the 27-nation bloc, the pair emphasized the EU wanted to avoid a repeat of the height of the region's first wave, in March last year.

"All non-essential travel should be strongly discouraged both within the country and of course across borders," von der Leyen told a media conference.

People in masks maintain social distancing as they queue to buy groceries in Thimphu, Bhutan. The Himalayan kingdom says it will only start vaccinating citizens on an "auspicious" date People in masks maintain social distancing as they queue to buy groceries in Thimphu, Bhutan. The Himalayan kingdom says it will only start vaccinating citizens on an "auspicious" date Photo: AFP / Upasana DAHAL

Brazil announced that it would finally receive two million doses on Friday of the British AstraZeneca/Oxford vaccine that were made in India. The jabs, which were originally due to arrive last week, will allow the second worst-hit country in terms of deaths to ramp up its Covid-fighting campaign.

Beijing puts several residential compounds under lockdown after the city saw a new locally transmitted virus outbreak in the Chinese capital's southern Daxing district. Some residents were transferred to a quarantine centre by buses while others were orde Beijing puts several residential compounds under lockdown after the city saw a new locally transmitted virus outbreak in the Chinese capital's southern Daxing district. Some residents were transferred to a quarantine centre by buses while others were ordered to remain indoors. Photo: CCTV

In northwest Brazil hospitals are battling drastic shortages of oxygen and hospital beds, with health workers describing harrowing scenes with dying patients gasping for breath due to the lack of available oxygen.

Elsewhere in Latin America, Colombia surpassed 50,000 Covid-19 deaths Thursday, while Mexico notched two new records with 1,803 deaths and 22,339 new infections over the past 24 hours.

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

Meanwhile the WHO has repeatedly warned that richer countries are hogging the vaccine -- and they are paying less for their doses, after negotiating favorable deals with manufacturers.

South Africa, for example, will pay 2.5 times more than most European countries for each Oxford-AstraZeneca shot, the South African health ministry has confirmed.

The US provided a boost to efforts to share out vaccines across the world, however, by announcing it intends to join the Covax initiative, a pool of doses supplied by countries and companies.

In Japan, questions are intensifying about the viability of hosting the Tokyo Olympic Games in six months' time -- an event which would require thousands of athletes to fly in from around the world.

Olympic chief Thomas Bach said there was "no reason whatsoever" to believe the games would not go ahead.

But many organizers of large-scale events are already grappling with the reality that the return to pre-pandemic normality may come later than previously hoped.

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."