Scientists Warn COVID-19 Might Spread Indoors

A group of 239 international scientists warned Monday that there is a significant risk of airborne transmission of COVID-19 indoors. Through a letter to be published in the journal Clinical Infectious Diseases, the group said that a considerable number of “cluster outbreaks of COVID-19” might be caused by airborne transmission. The group pleaded for the World Health Organization (WHO) and other international health agencies to recognize the risk of airborne transmission and come up with immediate mitigation measures. Scientists from 32 countries compose the group. They are experts in diverse fields such as virology, medicine, aerosol physics, exposure and epidemiology, and building engineering. From the Gizmodo report, the group also appealed to the WHO to “revise its recommendations.”

Businesses might need to implement more containment measures as they consider reopening this year. The scientists referred to current research showing that persons infected with COVID-19 exhale virus droplets while talking or breathing, which can travel further than the 1.5m social distance requirement. Prof. Lidia Morawska, director of the International Air Quality and Health Laboratory, emphasized the risk. “We are 100 percent sure about this,” she reported to the Los Angeles Times. Offices and other workplaces that require personal interaction could still harbor significant risks for their workers and clients. Even with strict distancing protocols, the virus might infect everyone inside the office if the carrier coughs or talks.

The group called on global stakeholders to address risk factors to contain the indoor spread of COVID-19. First in their list is revamping ventilation systems in buildings, from offices to schools and hospitals. Poorly ventilated buildings pose a high risk because the virus can end up recirculating into rooms through the air conditioning. In other cases, there might also be insufficient airflow to carry the virus out of the building. “At typical indoor air velocities, a 5-micron droplet will travel tens of meters, much greater than the scale of a typical room while settling from a height of 1.5m above the floor,” Prof. Morawska said.

Handwashing is also inappropriate for stopping airborne transmission. Instead, the group suggested avoiding overcrowding in public spaces and installing control measures in building ventilation. These include high-efficiency air filtration systems and ultraviolet lights that could kill germs or viruses. The scientists also propose simple strategies like “opening both doors and windows” in offices, which “can dramatically increase airflow rates in many buildings.”

“The risk of transmission goes up the longer air remains stagnant and the longer people continue to breathe it,” the scientists argued to the Los Angeles Times. Rethinking current strategies in combating the spread of coronavirus must now also include ways to curb airborne transmission. Aside from the experts’ proposals, businesses could also push for a total shift to online transactions to prevent personal interaction as much as possible. Before going back to business as usual, companies could strongly consider taking more radical changes in operations to stop the pandemic.