The new coronavirus is a serious threat to the elderly, as federal officials have been at pains to note recently. But they have stepped gingerly around advice for another group of Americans also at special risk from the infection: those with chronic health conditions.

It is not a small group. An estimated 60 percent of all Americans have at least one chronic health condition, and 40 percent have more than one. (The figures include the elderly.) Heart disease, cancer, diabetes — all of these can exacerbate a coronavirus infection, studies show, increasing the odds of severe disease and death.

Federal health officials have urged those in their 80s and older to sharply curtail their activities to reduce exposing themselves to infection. But beyond general advice to wash hands frequently and to avoid crowds, officials have said little about those who are younger and cope with chronic illnesses.

Now some experts are encouraging this broader swath of the population to take immediate action to protect themselves.