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Infection transmission and health
High humidity leads to loss of infectious influenza virus from simulated coughs
Indoor air quality is a critical factor in public health, especially in temperate climates where winter influenza outbreaks are common. Recent research demonstrates that relative humidity plays a decisive role in the aerosol transmission and infectivity of influenza viruses. In a controlled study, simulated coughs released influenza virus into an examination room at varying humidity levels. The results were striking; at low relative humidity (below 23%), the virus retained up to 77% of its infectivity after one hour, whereas at higher humidity (above 43%), infectivity dropped dramatically to as low as 14%. Most of this loss occurred within the first 15 minutes after aerosolization, regardless of particle size.
These findings align with broader message from Healthy Indoors, which highlights that dry indoor air not only increases the risk of airborne viral transmission but also impairs the body’s natural defences. Prolonged exposure to low humidity can damage mucous membranes and cilia, reducing the respiratory system’s ability to filter pathogens and increasing susceptibility to infections such as influenza and COVID-19.
Maintaining indoor relative humidity between 30–60% is therefore recommended, not only to reduce the infectivity of airborne viruses but also to support overall health, comfort, and productivity. This research underscores the importance of humidity management in public buildings, healthcare settings, and homes. As climate control technologies evolve, integrating humidity regulation into building standards could become a vital strategy for infection prevention and health promotion.
In reflection, the convergence of laboratory evidence and practical health guidance points to a simple yet powerful intervention: by ensuring adequate indoor humidity, we can significantly mitigate the spread of influenza and enhance well-being. This calls for greater awareness and action among policymakers, facility managers, and individuals alike.
Discover the full research
Curious to dive deeper into the research behind these findings? Click the link below to access the original scientific publication and explore the full study in detail.- Source
- National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC)
- Publication
- PLOS ONE
- Link
- https://www.researchgate.net/publication/235788069