President Trump on Wednesday invoked his son Barron’s positive coronavirus case in a push to physically reopen U.S. schools, saying that the 14-year-old was unaffected by the virus because of his immune system.

“Barron Trump, he had the corona-19,” the president told a crowd at a campaign rally in Des Moines, Iowa, referring to the novel coronavirus. “He had the China virus, right? And he had it for such a short period of time. I don’t even think he knew he had it because they’re young and their immune systems are strong and they fight it off 99.9 percent. And Barron is beautiful, and he’s free, free.”

Trump noted that his wife, first lady Melania Trump, shared the news that Barron had previously tested positive earlier that day. His son has since tested negative for the virus, the first lady said Wednesday.

“It happens. People have it, and it goes. Get the kids back to school. We’ve got to get them back to school,” the president told the crowd.

The private school Barron attends in the Washington, D.C., area, St. Andrew's Episcopal School, has conducted all-virtual classes thus far this school year.

Trump, who himself was diagnosed with the virus earlier this month, has consistently advocated for schools to physically reopen, despite concerns from public health experts about the possibility of school settings worsening the spread of COVID-19. Trump has at times falsely claimed that children are “almost immune” from the virus.

Children can contract COVID-19, though evidence indicates they are less likely to experience severe illness or death compared with their older counterparts. Elderly individuals are considered a high-risk population with respect to the coronavirus. The highly infectious disease has killed more than 215,000 people in the U.S. and more than 1 million worldwide.

Many schools across the country have elected to transition to partially virtual or all-virtual classes in order to blunt the spread of the virus. 

The first lady issued a written statement earlier Wednesday expanding on her own experience recovering from COVID-19 nearly two weeks after she and Trump were diagnosed with the virus.

She revealed that Barron tested positive for the virus after the first couple was diagnosed and exhibited “no symptoms.” She said that he since has tested negative. 

At Wednesday’s rally, Trump also discussed his own battle with the virus.

“It’s a little tough. You have a temperature, and you don’t feel good,” Trump said before touting the antibody cocktail that he received as part of his treatment.

Trump spent 72 hours at Walter Reed National Military Medical Center following his diagnosis. He was deemed able to resume public events by the White House physician last week and returned to the campaign trail on Monday.