Countries in Europe on Wednesday began easing travel bans on Britain put in place to contain a new strain of Covid-19 that UK officials believe spreads faster, as the US said it had now vaccinated one million people.
The discovery of the new strain set off alarm bells worldwide just as more countries began vaccination campaigns to halt a pandemic that has claimed more than 1.7 million lives since it emerged a year ago in China.
The European Commission urged EU nations to reopen their borders to Britain and replace the blockades with mandatory tests for arrivals.
France responded by relaxing its 48-hour blockade, allowing thousands of lorry drivers stranded in Britain a potential route home.
Under France's new rules, EU nationals and residents can travel providing they show a negative Covid test, though Britons remain barred.
Some truckers feared there was little chance of making it across the Channel in time for the holidays.
"Home for Christmas? Forget it," said Laurent Beghin, a French driver who delivered his cargo of paint on Sunday but was still stuck in England on Wednesday.
Scuffles broke out between police and truckers complaining of poor facilities and a lack of virus tests at one lorry park in southern England.
Passengers with negative virus tests on Wednesday also boarded the first Eurostar trains from London to France since border closures were introduced on Sunday, eager to spend Christmas with their families.
The Netherlands said it was lifting its travel ban on the UK Wednesday but noted that all passengers, including EU citizens, must have a recent negative test to enter.
Scientists are still trying to forge a plan to control the various strains, with Europe's branch of the World Health Organization meeting on Wednesday.
WHO's Europe director Hans Kluge wrote on Twitter that the organisation would "discuss strategies for testing, reducing transmission & communicating risks".
He added that "limiting travel to contain spread is prudent until we have better info".
The new strain of the virus, which has also been detected in small numbers elsewhere, appears to spread more easily than other types but experts say there is no evidence it is more lethal or resistant to vaccines.
Britain on Wednesday introduced restrictions on travel from South Africa over the spread of another new variant of coronavirus.
South African experts have been studying the new strand closely. Tulio de Oliveira of Kwazulu-Natal University said on Wednesday: "One thing that we think and evidence points in the same direction is that it is more transmissible."
As the European Union prepares to kick off vaccinations across the bloc on Sunday, the US Centers for Disease Control and Prevention announced the country -- the worst-affected in the world -- had passed one million vaccinations.
CDC director Robert Redfield said it was "an early but important milestone".
At the other end of the scale, Switzerland, Qatar and Dubai were doling out their first jabs on Wednesday and Serbia and hard-hit Mexico are next in line with plans start vaccinations on Thursday.
The co-founder of BioNTech -- one of the firms behind the vaccination -- has said its drug is "highly likely" to work against the mutated strain detected in Britain and otherwise can be adapted in six weeks.
In the US, infectious disease specialist Anthony Fauci received his jab as officials continued to seek to build public confidence.
But President Donald Trump's shock rejection of a $900 billion relief package passed by Congress raised concern.
Trump demanded changes to the bill including a big increase in the proposed $600 direct payments to less well-off Americans.
Lawmakers can override his veto if he goes through with it.
There was positive news in Australia, where Sydney eased lockdown restrictions for Christmas after the country's largest city reported a second day of new cases in the single digits.
Egypt, however, called off all New Year's celebrations in order to stem a rise in cases.
The Czech government also extended its state of emergency and announced tighter restrictions including closing shops in the face of a spike in cases.
And in Thailand, meanwhile, elephants dressed up in Christmas costumes for an annual tradition gave out pandemic-friendly gifts to schoolchildren: baskets of face masks.