Chris Christie said he has checked himself into a hospital after testing positive for Covid-19, the former New Jersey governor disclosed on Twitter Saturday.

The two-term Republican governor said he entered Morristown Medical Center this afternoon as a precautionary measure due to his history of asthma. He said he is “feeling good” and only have “mild symptoms.”

Christie participated in President Donald Trump’s preparations for Tuesday’s debate with Democrat challenger Joe Biden. He also attended last Saturday’s Rose Garden event, where Trump announced his Supreme Court pick Amy Coney Barrett.

On Friday, Christie tweeted that he felt fine without symptoms, adding that his Covid-19 test on Tuesday was negative.

Christie’s history of being overweight and chronic asthma could increase his risks of getting Covid-19 complications. In the past, he has said his obesity was “one of the struggles of my life.” In February of 2013, he had gastric-band surgery to help him lose weight.

In 2011, Christie was taken to a hospital following an asthma attack en route to an event.

Christie joins a growing list of aides and advisers close to Trump who have tested positive, including Trump’s campaign manager Bill Stepien and former White House Senior Adviser Kellyanne Conway. Trump himself had experienced “mild cough and some nasal congestion and fatigue” on Thursday but is “improving,” White House physician Sean Conley said on Saturday.