Speaking with Fox Business host Maria Bartiromo on Thursday morning, the president said he was ready to get back on the campaign trail and continue his rallies, adding that he was feeling “great.” Trump, who tested positive for the new coronavirus a week ago, spent four days in the hospital before returning to the White House on Monday.

“Remember you catch it and then you get better and then you’re immune,” Trump told Bartiromo.

Given how other diseases behave, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), said a reasonable assumption is that people who become ill will have some sort of immunity that either prevents infection or reduces the seriousness of the disease. However, there have been cases of people becoming reinfected, and it’s unclear how long any immunity people develop by recovering from the disease lasts.

The new coronavirus pandemic has continued to claim lives in America. As of Thursday morning, the country had more than 7.5 million cases and 211,000 deaths, according to a tracker maintained by Johns Hopkins University.

Trump’s said that “one death is too many” but has described the response as a “great success.” His remarks that the death toll “is what it is” and that people to not be afraid of the virus prompted critics to characterize him as dismissive of the number of lives lost. Since Trump’s own diagnosis, people have accused him of failing to acknowledge that his first-hand experience with COVID-19—which included top-of-the-line, round-the-clock medical care—is not the reality for most people.

In a video message on Thursday, Trump championed Regeneron, an antibody treatment, for being “unbelievable” and making him feel better “immediately.” He said his administration was working to make the drug available for anyone who was in the hospital and hoped to make it free of charge. The president confirmed to Bartiromo that Regeneron would be approved for emergency use.

As for why Trump was able to bounce back so quickly following his COVID diagnosis, he told Bartiromo it was because he is a “perfect physical specimen.” He denied that he had heart problems, diabetes or “any of the problems you read about,” adding that he’s in “good health.”