Former US secretary of state Hillary Clinton tweeted on Tuesday that she had a positive test result for the coronavirus, and described her symptoms as "mild".
Ms Clinton's husband, former president Bill Clinton, had a negative result and was in quarantine until their household was fully cleared.
On Twitter, the former Democratic presidential candidate said she was “feeling fine” and was thankful for the protection she had from the Covid-19 vaccines she received.
"I'm more grateful than ever for the protection vaccines can provide against serious illness," Ms Clinton wrote.
She called on all of her Twitter followers to "please get vaccinated and boosted if you haven't already".
The US has a seven-day average of 28,600 daily coronavirus infections, the US Centres for Disease Control and Prevention says.
The agency reports 75.3 per cent of US adults are fully vaccinated with two doses, while 48 per cent of those have had a booster dose.
A spokesman for the former president posted on Twitter that he would continue to get tested in the days to come.
Mr Clinton was a part of a campaign with former presidents Barack Obama, George W Bush and Jimmy Carter to compel Americans to be vaccinated against Covid-19.
Mr Obama announced this month that he had tested positive for the coronavirus.
Current President Joe Biden's administration is also dealing with several cases close to the White House.
Press secretary Jen Psaki on Tuesday announced she tested positive for coronavirus a second time, and will not be joining Mr Biden on his trip to Brussels for talks about Russian attacks on Ukraine.
"Thanks to the vaccine, I have only experienced mild symptoms," Ms Psaki wrote on Twitter.
"In alignment with White House Covid-19 protocols, I will work from home and plan to return to work in person at the conclusion of a five-day isolation period and a negative test."
The White House said Mr Biden had not tested positive with PCR tests this week.
Last week, Vice President Kamala Harris's husband Doug Emhoff tested positive for coronavirus. Ms Harris has not tested positive since.
The Associated Press contributed to this report