WASHINGTON — President Trump, whose government is leading an effort to combat the spread of the coronavirus in the United States, offered some tips on Wednesday to avoid getting sick, and as he did so, he revealed a little more about his lifelong aversion to germs.

“I do it a lot, anyway, as you’ve probably heard: Wash your hands,” he told reporters gathered at the White House for a news conference on the global epidemic. “Stay clean. You don’t have to necessarily grab every handrail unless you have to. You know, you do certain things.”

Mr. Trump’s self-declared germophobia is well documented. In his 2004 book, “How to Get Rich,” he detailed what he called a “personal crusade to replace the mandatory and unsanitary handshake with the Japanese custom of bowing.”

His stance on combating illness as president has in some ways matched how he behaved as a private citizen — “KEEP THEM OUT OF HERE!” he wrote on Twitter in 2014 days before an American aid worker infected with the Ebola virus in West Africa during a severe outbreak there returned to the United States. That has alarmed experts who have said he is not the right person to be leading the charge.