When three prison inmates were infected with the coronavirus in South Korea early last spring, corrections officers responded swiftly.

“Walk-thru” testing booths were installed in each of the country’s 54 prison compounds, masks were universally distributed, and prisoners had visitations curtailed.

Use of common areas was also restricted. Nine months later, the Asian nation – which has won plaudits globally for its effective and focused virus approach – has reported only one other Covid-19 cluster in a jail system that’s home to some 55,000 detainees: an outbreak of 11 cases.

Contrast that with the United States, where the virus spread to 2,200 people at California’s San Quentin State Prison over summer, killing 28.