Can Humidifiers Prevent the Flu? As winter unfolds, so does flu season, making it crucial to fortify ourselves against illness. Dry air is a common companion to winter, making both indoor and outdoor spaces cool and dry. In these conditions, airborne viruses like the flu and COVID-19 thrive, particularly as cooler weather pushes people indoors, sharing recirculated air and increasing the risk of infection. Adding moisture to the air with a humidifier is a simple ...