The US prepared to start its ­COVID-19 vaccination program on Monday as the nation's death toll edged toward 300,000, while Germany announced a partial lockdown over the holidays due to an explosion of cases.

Delivery trucks with special refrigeration equipment rolled out of a facility in Kalamazoo, Michigan, on Sunday as part of a public-private plan to ship millions of doses of the newly approved Pfizer-BioNtech vaccine to vulnerable Americans.

Courier services FedEx and UPS have deployed fleets of trucks and planes to carry their precious cargo - sometimes under armed guard - to all 50 states, where healthcare workers and nursing-home residents will be first in line.

"Vaccines are shipped and on their way," President Donald Trump tweeted. "Get well USA. Get well WORLD."

An initial 2.9 million doses are set to be delivered by Wednesday, with officials saying 20 million Americans could receive the two-shot regimen by year-end, and 100 million by March.

But the breakthrough comes at one of the darkest moments of the pandemic, with infections in the US and many other countries soaring, and health experts still struggling against vaccine skepticism, lockdown fatigue and uneven adherence to safety rules.

The US has the world's highest death toll of more than 299,000, and the largest number of cases, at 16.2 million - including more than 1.5 million new cases in just the past 

week.

Worldwide, there have been at least 1.6 million deaths since the outbreak emerged in ­December 2019, and 71.6 million cases overall.

The start of vaccination campaigns this week in the US - and also Canada - came as Germany announced a partial lockdown from Wednesday, with nonessential shops and schools to close in a bid to halt an "exponential growth" in infections.

The restrictions, agreed by German Chancellor Angela Merkel and regional leaders, will apply through the holidays until January 10. 

Europe's biggest economy has been severely hit by a resurgence of the coronavirus, with new daily infections more than three times their springtime peak. Daily death tolls last week approached 600.

Germany's hardest-hit states had already ordered new measures. Saxony state, where in some areas incidence rates have hit 500 per 100,000 people, will shutter shops and schools.

Italy, meanwhile, overtook Britain as the European nation with the highest death toll.

"I am worried about the two weeks of Christmas holidays... The battle still has not been won," Italian Health Minister Roberto Speranza warned as the country recorded 64,520 deaths, surpassing Britain's 64,267.