Olivia Troye, who was an aide to Vice President Mike Pence, served as a top organizer for the White House Coronavirus Task Force that Pence leads.
A lifelong Republican, Troye, who has since left the White House, said in a video released by the group Republican Voters Against Trump that the administration knew around mid-February that COVID-19 would become a big pandemic in the United States.
"But the president didn't want to hear that because his biggest concern was that we were in an election year and how was this going to affect what he considered to be his record of success," she said.
Troye said it was shocking to see Trump, who downplayed the virus in its early stages, referring to it as a hoax and saying everything would be OK.
"The truth is he doesn't actually care about anyone else but himself," she said in the video. "If the president had taken this virus seriously .... he would have slowed the virus spread, he would have saved lives."
Trump told reporters he did not know Troye. He said she was let go but wrote a "beautiful letter" praising the administration on her way out.
"I never met her," he said.
Pence, in comments to reporters, described Troye's words as sounding like those of a disgruntled employee who was playing politics during an election year.
A White House spokesman said her remarks were not true.
“Outside of generally watching the White House Coronavirus Taskforce from the overflow staff room, this disgruntled former detailee was never in private meetings with the president and her assertions have no basis in reality and are flat out inaccurate," White House spokesman Judd Deere said in a statement.
Biden, a former vice president, has sharply criticized Trump's handling of the pandemic, which has caused more than 195,000 USdeaths, and promised to institute a national plan to fight it if elected on Nov. 3.
Troye said it was an honor to serve in the White House but she wrestled during her time there with whether she made a difference because the president's actions were detrimental to the administration's efforts on the virus.
"It was awful," she said. "It was terrifying."