President Joe Biden will deliver a message of "hope" in an address to the nation Thursday after Congress passed his $1.9 trillion economic relief plan on the first anniversary of the start of the coronavirus pandemic.

Mourning the more than half a million Americans who died from Covid-19, Biden will use his first primetime television speech at 8:00 pm (0100 GMT Friday) to remember the "sacrifices" made, a White House official said.

He will cast the struggle against the virus and the ensuing economic fallout as "the greatest operational challenge the country has faced," said the official, who did not want to be identified.

And he "will lay out the next steps he will take to get the pandemic under control, level with the American people about what is still required to defeat the virus, and provide a hopeful vision of what is possible if we all come together."

While a somber occasion -- 12 months after the World Health Organization declared a pandemic and then-president Donald Trump shut US borders to travel from Europe -- that note of optimism will be key.

"There is real reason for hope folks, I promise you," Biden said Wednesday, previewing his remarks.

With vaccines starting to make a real impact and production soaring, the mood is shifting in the United States, with the economy predicted to be entering a sustained rebound.

Giving that progress a massive boost is the American Relief Plan passed this week by Congress. It dishes out $1,400 payments to most Americans, helps the unemployed, expands public health care and ramps up funds for vaccinations.

On Friday, Biden will sign the bill, which although opposed by all Republican lawmakers in Congress has voter approval ratings of 60 percent and above.

"There is light at the end of the tunnel," Biden said.

Help is on the way

Biden has barely traveled since becoming president. The White House says he wanted to keep his head down, focusing on the political work needed to get the stimulus plan through Congress.

Now the Democrat appears set to spend more time in Air Force One and on the road, starting with a trip to Pennsylvania next Tuesday.

He is set to hold the first formal press conference of his presidency later this month and plans are being drawn up for an address to the joint session of Congress.

And in support will be a small army of senior staff and Biden's wife Jill who will travel nationwide delivering the message that "help is on the way," as White House Press Secretary Jen Psaki put it.

The thrust of the Biden blitz will be selling Americans on the stimulus package, building on the warm reception so far to create durable political capital ahead of next year's congressional midterm elections.

Biden and his top aides have talked frequently about how the Barack Obama and Biden administration failed to adequately market the 2009 economic rescue package that they say saved the country from entering a depression after the 2008 financial meltdown.

In the 2010 midterms, voters turned fiercely against the Democrats and this time, the White House says, it wants to roll out a proper "victory lap."

"The passage and signing of the bill is just the beginning," Psaki said Wednesday.

"He will be hitting the road, the vice president will be hitting the road, the first lady will be hitting the road," Psaki said. "We will have people out communicating directly in communities."