PHILADELPHIA (AP) — The nation’s jails and prisons are on high alert for the new coronavirus. The fear that COVID-19 will spread through vast inmate populations has prompted the mass sanitizing of jail cells and intensified prisoner screenings.

So far, there haven’t been any reported cases of the virus in any jails or prisons in the U.S. But more people are incarcerated per capita here than in any other country in the world. Prisons have become a hot spot in other nations touched by the outbreak.