A POLITICO analysis, combining health data from researchers with a tracker of Covid-19 infections from The New York Times, found that one in three of the counties now seeing rapid spread of coronavirus also have some of the highest rates of heart disease among people 65 and older, which doctors say can leave people more vulnerable to complications.

Across the U.S., infections are on track to double within a week in more than 240 counties with more than 50 or more Covid-19 cases, according to the Times data. Of these, nearly 90 counties already have elevated rates of heart problems, with 2016 data showing that 20 percent or more of their older residents on Medicare were hospitalized for cardiovascular disease over a two-year period.

These same communities have a higher population of nonwhite residents and a lower median income than the national average — reflecting reports from the ground that low-income communities of color are bearing the brunt of the public health crisis.