Photo/Illutration Hiroshi Nishiura, a professor of theoretical epidemiology at Hokkaido University who leads the health ministry panel on coronavirus infection clusters (Asahi Shimbun file photo)

Up to 420,000 people in Japan could die of COVID-19 if people slack off on social distancing and other measures to prevent novel coronavirus infections, a health ministry panel said on April 15.

Such inaction by the public could lead to about 850,000 people developing severe symptoms of the disease, and each one of them would require a ventilator, the panel on coronavirus infection clusters warned.

The estimates were based on the assumption that one infected person will transmit the virus to 2.5 people and the reported 49-percent fatality rate among COVID-19 patients with severe symptoms in China.

Hiroshi Nishiura, a professor of theoretical epidemiology at Hokkaido University who leads the panel, again emphasized the importance of social distancing and refraining from nonessential activities and travel outdoors.

He said a reduction in human-to-human contact by 80 percent from normal times will certainly lower the number of patients with severe symptoms as well as the death toll.

The panel has been trying to compile numerical figures on the effects of social distancing and other preventive practices in areas under the government’s state of emergency.

“Think about having a conversation with someone 1 to 2 meters apart, and count it as one contact,” Nishiura said. “If you had 10 contacts per day before the virus outbreak, can you reduce the number to two? I want people to be creative. Try teleworking and other things, please.”