A simulation using a supercomputer shows the risk of infection with the Omicron coronavirus variant increases when people talk to each other within a distance of 50 centimeters even when they are wearing masks.

A team of researchers from the RIKEN research institute and others conducted the simulation on the spread of coronavirus droplets using the Fugaku computer.

The simulation was based on past cases of cluster infections on the assumption that the Omicron variant is 50 percent more infectious than the Delta variant.

The results show that the average rate of infection during a 15-minute conversation with a person infected with the Omicron variant who was wearing a mask was almost nil when other people are one meter or more apart.

But the rate increased to around 14 percent when they are within 50 centimeters from each other.

The researchers warn people should keep a sufficient distance from each other even when they are wearing masks.

When an infected person was not wearing a mask, the rate of infection rises to about 60 percent within a distance of one meter, and nearly 100 percent within 50 centimeters.

In the case of sitting next to each other at an event, the rate of infection was 40 percent to people sitting next to a person infected with the virus who was wearing a mask. But it rises to 50 percent to people nearby if the infected person was not wearing a mask.

The researchers found maintaining a distance helped to keep the infection risk low.

The researchers say the risk of infection should remain low during classes at schools if people wear masks and keep a sufficient distance.

They say one possible countermeasure may be to have more frequent breaks for a short time to prevent droplets from filling rooms after conversations.

The team leader Tsubokura Makoto says that in addition to wearing masks, it is important to think about the time and distance when people contact or talk with others.