WASHINGTON (BLOOMBERG) - White House coronavirus adviser Dr Scott Atlas, who won President Donald Trump's favour by advocating the loosening of social distancing restrictions during the pandemic, resigned his post on Monday (Nov 30), according to a White House official.

His departure closes a controversial tenure in which the neuroradiologist without a background in infectious disease prevention or public health drew the ire of other members of the coronavirus task force for urging the president to abandon lockdowns, describing such efforts as harmful to Americans.

In a resignation letter obtained by Fox News, which first reported his departure, Dr Atlas said he was leaving the administration because his federal employment status was expiring.

Temporary workers considered "special government employees" can only work 130 days per year.

"As time went on, like all scientists and health policy scholars, I learned new information and synthesised the latest data from around the world, all in an effort to provide you with the best information to serve the greater public good," Dr Atlas wrote.

"But, perhaps more than anything, my advice was always focused on minimising all the harms from both the pandemic and the structural policies themselves, especially to the working class and the poor."

Dr Atlas's approach drew widespread controversy, with longtime public health officials within the Trump administration questioning the scientific justification for his claims and the faculty senate of Stanford University - where Dr Atlas is a Hoover Institution senior fellow - passing a resolution saying he took actions that "promote a view of Covid-19 that contradicts medical science."

Centres for Disease Control and Prevention Director Robert Redfield was overheard by a NBC News reporter earlier this year telling a colleague of Dr Atlas that "everything he says is false."

Dr Atlas apologised earlier this month for conducting an interview with Russia's state-controlled RT network, saying he did not realise the organisation's Kremlin ties.

Dr Atlas did not appear at a pre-Thanksgiving briefing by other members of the coronavirus task force, where officials urged Americans to be vigilant as cases surged nationwide.

The number of Americans hospitalised with Covid-19 climbed to a record high of 93,238 people on Sunday.

In California, Governor Gavin Newsom said the state was considering a return to stay-at-home orders.

More than 267,000 people in the US have died of the illness, according to Johns Hopkins University.