Japan supercomputer finds ways to cut risk of airborne virus infection

Operating trains with windows open and limiting number of passengers

 may help reduce risk of infection

REUTERS

Supercomputer-driven models simulated in Japan have suggested that operating commuter trains with windows open and limiting the number of passengers may help reduce the risk of novel coronavirus infection, as scientists warn the virus may spread in the air.

In an open letter published Monday, 239 scientists in 32 countries outlined evidence they say shows floating virus particles can infect people who breathe them in.

The World Health Organization (WHO) acknowledged “evidence emerging” of airborne transmission, but said it was not definitive.

Even if the coronavirus is airborne, questions remain about how many infections occur through that route. How concentrated the virus is in the air may also decide contagion risks, said Professor Yuki Furuse of Kyoto University.

In the open letter, scientists urged for improvements to ventilation and the avoidance of crowded, enclosed environments — recommendations Japan broadly adopted months ago, according to Shin-ichi Tanabe, one of the co-authors of the letter.

“In Japan, the committee for COVID-19 countermeasures insisted on the 3Cs at an early stage,” said Tanabe, a professor at Waseda University in Tokyo, referring to Japan’s public campaign to avoid closed spaces, crowded places and close-contact settings. “This was ahead of the world.”

As the nation tamed the pandemic, with over 19,000 confirmed cases and 977 deaths so far, Economy Minister Yasutoshi Nishimura credited its success to the 3Cs and its cluster-tracing strategy.

The recent study by Japanese research giant Riken using the world’s fastest supercomputer, the Fugaku, to simulate how the virus travels in the air in various environments recommended several ways to lower infection risks in public settings.

Makoto Tsubokura, the study’s lead researcher, said that opening windows on commuter trains can increase ventilation two- to threefold, lowering the concentration of ambient microbes.

But to achieve adequate ventilation, there needs to be space between passengers, the simulations showed, representing a drastic change from the custom of packing commuter trains tightly, for which the nation is notorious.

Other findings advised the installation of partitions in offices and classrooms, while hospital beds should be surrounded by curtains that touch the ceiling.