When three prison inmates were infected with the COVID-19 virus 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 distributed universally 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 of 11 infections in a jail system that’s home to some 55,000 detainees.