Hundreds of thousands of people around the world are jailed in crammed cells under unsanitary conditions, fertile ground for the spread of the coronavirus, but many governments have yet to adopt measures that could prevent the pandemic from taking hold there.

Inside many of these poorly maintained prisons, safeguards such as quarantines, social distancing, sanitary items and even proper health training are rare, say human rights groups and prison monitors. And the restrictive measures some detention facilities have taken, such as suspending prison visits, have sparked tensions and even unrest from Latin America to Europe to the Middle East.