As coronavirus infections continue to spread nationwide and grave risks loom for detainees in correctional and detention facilities, judicial authorities are stepping up measures to prevent a petri-dish effect like that aboard the Diamond Princess cruise ship, where more than 700 people became infected with COVID-19.

The novel coronavirus has already affected three correctional facilities — in Osaka, Tokyo and Hokkaido — where a total of 10 people have tested positive, putting staff and inmates at risk.

Concerns are rising among authorities and rights groups that an exponential spread of the virus in such facilities would eventually lead to staff shortages and problems in accessing medical care.