Maddow was absent from her show about two weeks after she revealed that she was in close contact with someone who had tested positive for the infection.
Maddow returned to the air on Thursday night and said the person was her 21-year-old partner, Susan Mikula.
“At one point, we really thought it was a possibility it might kill her, so I was gone,” Maddow said.
Maddow said her partner, whom she described as “the center of my life,” is recovering well.
Maddow said she tested herself negatively for coronvirus and gave a Thursday show from her home in New York, where she isolated herself.
Hosts Show Rachel Maddow, The most watched program for current affairs MSNBC, which has been running for more than a decade.
At the request of her viewers, Maddow called on the public to take the virus seriously.
“Don’t understand the thing. “Do what you can to keep her from getting it,” she said. “You’ll really have it at home for Thanksgiving next week without people coming.
“Yeah, it’s going to suck, but it’s going to suck so much less than you or someone in your family gets sick. “Trust me,” Maddow added.
Coronavirus infections continue to rise in the United States. According to official figures, health officials reported 187,396 new cases on 19 November.
About 5,000 of these infections have been reported in Maddow’s hometown of New York, where 24,000 people have died from the disease.
More than 250,000 people died across the country after the infection.
More news from the Associated Press