The US has become the first country to record more than half a million deaths with coronavirus.
There have now been 500,071 COVID-related fatalities in the country, and more than 28 million people have been infected, according to the Johns Hopkins coronavirus tracker.
President Joe Biden and Vice President Kamala Harris are to commemorate the huge loss of life at a White House event that will include a speech by the president, a moment of silence and a candle-lighting ceremony.
In a statement, the president said more Americans had died “in a single year of this pandemic than in World War One, World War Two, and the Vietnam War combined”.
He added: “We, as a nation, must remember them so we can begin to heal, to unite, and find purpose as one nation to defeat this pandemic.”
Mr Biden asked all US citizens to “observe a moment of silence at sunset”.
And he has ordered the nation’s flag to be flown at half mast at the White House, on all public buildings and grounds, and at military posts and naval stations until sunset on Friday.
Brazil has the second highest number of coronavirus deaths globally with about 250,000.
The fact the US leads the world in both death and infection numbers reflected poor planning by the Trump administration, President Biden has previously said.
Confirming the US had bought enough doses “to vaccinate all Americans”, he accused Mr Trump of failing to manage the vaccine rollout.
“While scientists did their job in discovering vaccines in record time, my predecessor – I’ll be very blunt about it – did not do his job in getting ready for the massive challenge of vaccinating hundreds of millions,” he said.
In December, the US’s average daily deaths linked to COVID-19 touched 2,276 with one daily total exceeding the 2,977 people who lost their lives in the 9/11 terror attacks.
Indigenous Americans are the worst-affected racial group as a percentage of population, recording almost 211 deaths per 100,000 people, Statista said.
Despite Mr Biden’s criticisms, there is cause for hope in the vaccine rollout, with official statistics saying about 64 million jabs had so far been given.
That puts the US on course to exceed the president’s stated target of 100m doses in his government’s first 100 days, though progress was hampered by the recent freezing weather.
And case numbers are also dropping – down to around 100,000 per day this month from 250,000 in January.
It is a far cry from Mr Trump’s optimistic prediction last April, that, even if it did nothing, the US would lose 50,000 to 60,000 people to the virus.