Not only does fall bring cooler temperatures, it also marks the start of cold and flu season. Alongside remedies like elderberry and vitamin C to support your immune system, a new study from Yale University suggests that using a humidifier may help reduce the risk and severity of influenza.
In the study, researchers placed two groups of mice in different environments for several days: one group in low humidity and the other in normal humidity. Both groups were then exposed to influenza A. The mice kept in normal humidity fared better, showing fewer signs of illness and a stronger ability to clear the infection than those kept in dry conditions.
The researchers concluded that dry air can impair the trachea’s ability to clear pathogens and debris, and that dehydration in low-humidity conditions can limit the body’s ability to fight infection. Proper mucociliary function—how the airways move mucus and trapped particles out of the lungs—appears to be more effective at normal humidity levels, helping the immune system control viral invasion.
However, the authors cautioned that increasing indoor humidity is not a one-size-fits-all solution. Influenza A can still thrive in tropical and subtropical climates, and the relationship between humidity, viral survival, and immune response is complex. More research is needed to clarify how humidity affects flu transmission and outcomes across different environments and human populations.
For people looking to reduce flu risk at home, maintaining moderate indoor humidity may be a useful part of a broader strategy that includes vaccination, good hand hygiene, and supportive measures like staying hydrated and using over-the-counter remedies as appropriate. Humidifiers can help relieve dry air symptoms and support airway function, but they should be used carefully—overly high humidity can encourage mold and dust mites, so aiming for a balanced range is important.
In summary, the Yale study highlights that maintaining normal indoor humidity might support respiratory defenses and improve recovery when faced with influenza A, but further studies are required to understand how best to apply this finding across different climates and settings.