Fighting COVID: Add Mist To Your List

Fighting COVID is foremost on everyone’s mind. We sanitize our hands, wear masks, social distance, and do everything else healthcare specialists tell us to do. But there is one thing our health and disease experts are recommending that you’re probably missing: humidity.

For centuries, studies have shown a correlation between dry air and respiratory illnesses. Now, recent studies from Yale University, Harvard Medical School, and the National Academy of Sciences all agree that an indoor relative humidity (RH) of 40-60% not only slows the spread of coronavirus, it also helps your immune system fight off respiratory illnesses.

In a March 2020 article, Yale researchers stated that dry air makes it easier for airborne viral particles of viruses, such as COVID-19, to travel. This is because airborne droplets containing viruses shrink by evaporation, so they are lighter and float longer. When indoor air is at 40-60%RH, these particles retain moisture, so they are heavier and fall out of the air.

This Yale study agrees with a statement made by Dr. Stephanie Taylor, an Infection Control Consultant at Harvard Medical School, who says public buildings like hospitals and schools should maintain 40-60%RH year-round.

“Relative humidity of 40-60% in buildings will reduce respiratory infections and save lives,” Dr. Taylor said in a statement on the website 40to60rh.com.

Dry air also hinders the ability of cilia, the microscopic hair-like projections on our cells, to remove viral particles from our airways. In a review published online in March 2020 in the Annual Review of Virology, Yale immunobiologist Akiko Iwasaki cited experiments that showed mice kept in 50%RH were able to expel an inhaled virus and showed better immune responses.

“Studies have shown there is a sweet spot in relative humidity,” Dr. Iwasaki said in a statement on 40to60rh.com. “Air of between 40% and 60% [relative humidity] shows substantially less ability to transmit viruses and allows our nose and throat to maintain robust immune responses against them.”

A 2019 study by the Proceedings of the National Academy of Sciences (PNAS) supports Dr. Iwasaki’s research. The PNAS study found that low humidity not only hindered cilia’s ability to expel viral particles, it also hurt the ability of flu-damaged lung cells to repair themselves. Low humidity also made infected cells less able to alert neighboring cells to the virus and fight its spread.

Does this all mean that you should take the humidity in your home as high as you can? The research all says no. 40-60%RH is the ideal setting. Relative humidity levels over 60% can actually help viruses spread by dropping viral particles onto surfaces and keeping them alive longer.

It is important to note that all of this research applies only to the spread of airborne viral droplets. To prevent person-to-person transmission, you will still need your mask and hand sanitizer and to practice social distancing.

Have questions about adding a humidifier to your home? Our humidifier experts can be reached at 800-547-3888. Whether you decide on one of our models, or another brand, we are happy to help you protect your home and family.