US President-elect Joe Biden on Monday urged Americans to wear masks to prevent the spread of coronavirus and not consider it a "political statement," as he named the scientists who will lead his administration's response to the pandemic.

Mindful of Covid-19's nationwide surge, the Democrat said that after a divisive election Americans must unite around a "shared goal" of defeating the virus.

"So please, I implore you, wear a mask," Biden said in Wilmington after he and Vice President-elect Kamala Harris held a virtual briefing with his newly named Transition Covid-19 Advisory Board.

"Do it for yourself, do it for your neighbor," he added. "A mask is not a political statement, but it is a good way to start putting the country together."

Joe Biden attends a coronavirus briefing on October 28, 2020 in Wilmington, Delaware, with participants in the briefing including two people he later named as co-chairs on his Covid-19 advisory board: Vivek Murthy and Marcella Nunez-Smith
Joe Biden attends a coronavirus briefing on October 28, 2020 in Wilmington, Delaware, with participants in the briefing including two people he later named as co-chairs on his Covid-19 advisory board: Vivek Murthy and Marcella Nunez-Smith GETTY IMAGES NORTH AMERICA / Drew Angerer

Biden, 77, has routinely worn face coverings over the past several months, while President Donald Trump has largely eschewed them and held open-air rallies where thousands of supporters crowded together, often maskless.

Scientists in Trump's own administration have warned that Americans must embrace mask-wearing as they face a surging pandemic with colder months ahead.

"We're still facing a very dark winter," Biden said. "The bottom line: I will spare no effort to turn this pandemic around once we're sworn in on January 20."

Biden spoke shortly after US company Pfizer and Germany's BioNTech said a vaccine they had jointly developed had so far proven 90 percent effective in preventing infections in ongoing Phase 3 trials -- news that cheered scientists, politicians and markets.

The president-elect applauded the announcement, but insisted a mask still remains "the most potent weapon" against the virus, and that "today's news does not change that urgent reality."

US President-elect Joe Biden delivers remarks at The Queen in Wilmington, Delaware, on November 9, 2020.President Donald Trump was still refusing to concede his election loss November 9, 2020, but Democrat Joe Biden plowed ahead anyway with the first meet
US President-elect Joe Biden delivers remarks at The Queen in Wilmington, Delaware, on November 9, 2020.President Donald Trump was still refusing to concede his election loss November 9, 2020, but Democrat Joe Biden plowed ahead anyway with the first meeting of a parallel coronavirus task force, initiating an awkward and potentially volatile transition period. AFP / Angela Weiss

His advisory board will be led by three co-chairs: epidemiologist and former Food and Drug Administration (FDA) commissioner David Kessler, former surgeon general Vivek Murthy, and Yale public health professor Marcella Nunez-Smith, according to a statement from Biden's transition team.

The board, which Biden says will help lay out a blueprint for action beginning on Day One of his presidency "built on a bedrock of science," will have 10 members, ranging from immunologists and epidemiologists to biodefense experts and leading public health officials.

Among them is Rick Bright, the virologist who was ousted by the Trump administration in April from his post as head of the Biomedical Advanced Research and Development Authority, the agency charged with developing a coronavirus vaccine.

A month later he warned Congress that Trump had no "master plan" to fight the pandemic and was unprepared to distribute enough vaccines to immunize millions of Americans.

The panel also includes former Barack Obama administration officials including one of his health care reform architects, Ezekiel Emanuel, and former National Security Council member Luciana Borio.

Covid-19 has left 237,000 Americans dead and is surging across the country, which last week voted out Donald Trump in a nailbiting election.

According to a Johns Hopkins University tracker, new US cases have topped 100,000 every 24 hours for several days running, and have topped 10 million in total -- showing no sign of slowing despite Trump's claim the world's biggest economy is "rounding the corner."