US President Joe Biden told Americans on Thursday not to let down their guard in the fight against coronavirus as the country is set to hit 100 million vaccinations by the weekend.

"I'm proud to announce that tomorrow [Friday], 58 days into my administration, we will have met my goal of administering 100 million shots," he said in a White House speech.

Speaking alongside Vice President Kamala Harris, Biden said it was "not a time for relaxation" as he called for social-distancing rules and mask-wearing advice to be observed.

"Now's not the time to let down our guard," he added. "Scientists have made clear that things may get worse as new variants of this virus spread."

Don't be like Europe, Biden warns

The accelerating vaccine rollout is dovetailing with falling infection rates, leading to optimism that the world's biggest economy is headed for a powerful rebound.

"Please, please, don't let what’s happening — you see happening in Europe and you see on television," Biden said in an apparent reference to Europe's faltering inoculation drive. 

Americans need to take their opportunity to get vaccinated when it becomes available, he said, addressing the large sectors of society that are so far resisting.

However, the US has handed out 33.8 doses for every 100 people, according to figures compiled by Our World in Data.

The European Union, by contrast, has issued 11.9 vaccine doses for every 100 Europeans, the same report said.

Trump throws weight behind jab drive

Former President Donald Trump only this week called directly on his supporters, who form one of the biggest groups of vaccine opponents, to embrace the shots, saying "it's a great vaccine, it's a safe vaccine."

But with vaccine production churning out in the United States, the Biden administration says it is now on the point of being able to send surplus shots of the AstraZeneca version to neighboring Mexico and Canada.

Biden's press secretary, Jen Psaki, said that 2.5 million doses were being lined up for Mexico and 1.5 million for Canada. A total of 7 million doses are stockpiled

Biden said on March 11 that he wanted to make sure "Americans are taken care of first" before sending any vaccines abroad.

Britain's Financial Times reported earlier this month that European Commission President Ursula von der Leyen had asked Washington consider sending doses to Europe amid a row with AstraZeneca.

The Anglo-Swedish pharmaceutical giant said it would supply less than half the planned number of COVID-19 vaccines to the EU in the second quarter, after the firm's efforts to remedy a slew of problems ran into further trouble.

AstraZenenca says it will now only deliver about 76 million out of a planned 180 million doses to the bloc.

jf/msh (AFP, dpa, Reuters)