Published Date: 04/23/20
Past studies have shown that a simple humidifier can be effective in preventing the spread of cold and flu in hospitals and preschools. With the COVID-19 pandemic sweeping the world, research shows humidifiers may be effective in slowing and preventing the spread of the virus as well.
In researching the spread of the flu, Harvard Medical School graduate Dr. Stephanie Taylor said, “When we dry the air out, droplets and skin flakes carrying viruses and bacteria are launched into the air, traveling far and over long periods of time. The microbes that survive this launching tend to be the ones that cause healthcare-associated infections. Even worse, in addition to this increased exposure to infectious particles, the dry air also harms our natural immune barriers which protect us from infections."
This theory was tested in a preschool by researchers at the Mayo Clinic. Throughout the winter, researchers humidified half the classrooms in a preschool and left the others as is. At the end of the three month experiment, children who were in the humidified classrooms were assets two-thirds less from the flu than ones that weren’t humidified.
Preliminary research shows that the technique may be beneficial in mitigating the spread of COVID-19 as well.
In 2019, a groundbreaking study was published by a research team at Yale University medical School (Kudo et al., National Academy of Sciences, 2019). The study demonstrated how an animal host’s immune system’s ability to fight respiratory viral infections is decreased when ambient humidity is low.
Dr. Nancy Gough of Johns Hopkins University reviewed the Yale study and said, “When the temperature drops, the heat comes on. This reduces the amount of humidity in the air. It turns out this isn’t just uncomfortable; it also impairs the innate immune system in the respiratory tract.”
Akiko Iwasaki, Waldemar Von Zedtwitz Professor of Immunobiology and professor of molecular, cellular, and developmental biology at Yale, and an investigator for the Howard Hughes Medical Institute is further studying the phenomenon. Her lab explains that when moisture in the air drops, it provides a clear bath for airborne viral particles, like COVID-19.
In addition, the ability of cilia in the respiratory tract to expel viral particles is lessened in dry, warm air. Cilia work to help keep the airway clear of dirt and mucus and allow us to breathe easily without irritation.
In past studies, ideal humidity to help prevent the transmission of colds and the flu was 40-60%. You can track the humidity in your classroom with a simple hygrometer, which can be purchased for about $10. Depending on the size of your classroom and your climate, you may need one or several humidifiers. Ensure that you only use cold mist in rooms where children are present to prevent accidental burns.