White House chief of staff Mark Meadows, who has frequently appeared at public events without wearing a mask, has been diagnosed with COVID-19, a source familiar with the situation told Reuters on Friday.
It was not immediately clear when or how he was infected.
Another campaign assistant, Nick Trainer, also tested positive for the virus, according to the source.
Meadows, Trump’s top adviser and former North Carolina lawmaker, regularly accompanied US President Donald Trump through the last frenzied days of campaign rallies leading up to Tuesday’s presidential election.
Meadows, who was at a White House election night attended by dozens of Trump followers, is the latest official in Trump’s inner circle to contract COVID-19, which has killed more than 236,000 Americans.
Trump has regularly downplayed the severity of the virus, which has increased in recent weeks and is set to continue to do so through the winter. He contradicted public statements by top health experts, even after an epidemic gripped the White House in October.
The president was briefly hospitalized at the time after being infected with the virus. His wife and son Barron also tested positive for the coronavirus in October.
His national security adviser, Robert O’Brien, was also sickened by the virus. Another Trump friend, former Republican presidential candidate Herman Cain, died of coronavirus in July after attending one of Trump’s rallies.