Dry indoor spaces 'perfect conditions' for Covid spread in winter, supercomputer finds

A humidifier in the home or office could help prevent spread of contagion, Japanese research says

• 

  A member of a healthcare team works at a drive-through COVID-19 testing center at Chadstone Shopping Centre in Melbourne, Australia. EPA

• 

  People walk past the Cobble Hill Cinemas movie theater in New York City. With theaters closed in New York and Los Angeles and would-be movie goers across the country choosing to stay in, US cinemas are sending out a desperate SOS -- so far unanswered by Congress and studios. AFP

• 

  A man wears face mask as he walks past the Klang river mural in Klang, Malaysia. Klang district in state of Selangor is within the red zone area under the Conditional Movement Control Order (CMCO) after increasing numbers of cases of COVID-19 disease. EPA

• 

  Health workers walk through the Rocinha slum to test people for COVID-19 as part of a rapid test campaign by the civilian organization "Bora Testar," or "Let's Test" in Rio de Janeiro, Brazil. Financed by crowdfunding and donations, the organization says it aims to test up to 300 people in the slum. AP Photo

• 

  An elderly woman wearing a face shield to curb the spread of the new coronavirus waits her turn in line to be given coupons provided by the municipality of Iztapalapa to buy groceries in Iztapalapa, Mexico City. The municipal government of Iztapalapa is providing coupons to help poor families cope with the hardship created by the new coronavirus pandemic economic slowdown. AP Photo

• 

  American poet Louise Gluck reacts after winning the 2020 Nobel Prize for Literature, at her home in Cambridge, Massachusetts, U.S. REUTERS

• 

  French Economy and Finance Minister Bruno Le Maire (R) and French Health Minister Olivier Veran, wearing protective masks, look on during a press conference about the situation of the Covid-19 pandemic caused by the novel coronavirus in France, at the Health Ministry in Paris. AFP

• 

  A health worker tests a migrant domestic worker from Africa for the coronavirus disease (COVID-19) at a hotel, before she travels back to her country, in Beirut suburbs, Lebanon. REUTERS

• 

  Miyana Moffett watches a ride at the Mississippi State Fair as it opens with coronavirus disease (COVID-19) restrictions in Jackson, Mississippi, U.S. REUTERS

• 

  A visitor is reflected in glass as he takes a picture of a replica of the head of Michelangelo's sculpture "David" at the National Museum of Fine Arts Museum on its opening day after closing for over half a year due to the lockdown to curb the spread of COVID-19 in Santiago, Chile. AP Photo

• 

  People arrive at Beijing Railway Station after an eight-day National Day holiday following the outbreak of the coronavirus disease (COVID-19) in Beijing, China. REUTERS

• 

  People walk past a poster to raise awareness about wearing a face mask, as the coronavirus disease (COVID-19) outbreak continues, in Mexico City, Mexico. The poster reads: "For courage, wear it" REUTERS

• 

  A homeless person naps on a street bench reading "over 6,200 have died in LA from Covid-19", in Los Angeles, California. AFP

The world's fastest supercomputer has calculated a heightened risk of coronavirus spread in dry indoor spaces – pointing to a rise in cases in colder climates during the winter months.

The processing power of Japan's Fugaku supercomputer has been used in the fight against the pandemic for months.

Its latest findings indicated that humidity can have a large effect on the dispersal of virus particles, suggesting humidifiers may limit infections during times when window ventilation is not possible.

A study by Japanese research institute Riken and Kobe University tasked Fugaku with modelling the emission and flow of virus-like particles from infected people in a variety of indoor environments.

Air humidity of lower than 30 per cent resulted in more than double the amount of aerosolised particles compared to levels of 60 per cent or higher, the simulations showed.

The study also suggested that clear face shields are not as effective as masks in preventing the spread of aerosols.

The Riken research team, led by Makoto Tsubokura, has used the Fugaku supercomputer to model contagion conditions in trains, work spaces, and classrooms.

The simulations showed that opening windows on commuter trains can increase the ventilation by two to three times, lowering the concentration of microbes.

“People’s blind fear or unfounded confidence against the infection of Covid-19 is simply because it is invisible,” Dr Tsubokura said.

Earlier this month, the US Centres for Disease Control and Prevention updated its guidance to say coronavirus can linger in the air for hours.

The CDC had not made a direct link about the role airborne transmission is playing in the spread of the virus.

But the public health agency's new advice said aerosolised virus particles can, and do, infect others under certain circumstances.

The capacity of coronavirus to spread through minuscule droplets, which float in the air long after an infected person coughs, breathes, or sneezes, was noted by authorities in China in February, very early in the outbreak.

Circumstances where confirmed airborne transmission has occurred, according to the CDC, include enclosed spaces where people were exposed shortly after the infected person left.

Aerosolised transmission has also occurred when infected people were shouting, singing or exercising, which increased the concentration of “suspended respiratory droplets in the air space”.

In addition, inadequate ventilation can increase the risk of airborne transmission by allowing the build-up of suspended small respiratory droplets and particles, the CDC said.

The agency said most people became infected by inhaling large droplets through close contact with sufferers.

When it is fully operational next year, experts are hoping the Fugaku machine will be able to help narrow the search for effective treatments for coronavirus.

The computer, which fills a room, is housed in the city of Kobe and is named after Mount Fuji – Japan's often snowcapped highest mountain and an active volcano.