Yale (USA), May 2019

Yale study: How humidity protects against flu

We’re very familiar with flu waves in the winter months and we do our best not to become sick. We get a flu jab, use disinfectants rigorously, and keep well away from anyone who coughs or sneezes. So is there anything else we can do?

A new study from Yale University researcher Akiko Iwasaki has shown that a relative humidity of 50 percent offers excellent protection against catching the flu. Although earlier studies had shown a clear link between certain ambient conditions—such as dry room air—and an increased transmission of flu viruses, this study is the first scientific paper to uncover the mechanism by which humidification works to significantly lower the rate of morbidity and death in mice, and whose findings are also directly applicable to humans.

The outstanding results achieved by the immunobiology lab run by Dr Iwasaki have supplied new and conclusive answers to key questions about the health benefits of a well-balanced humidification system.

Dr Iwasaki’s work answers these questions::

  • How does well-balanced air humidity affect people who are exposed to the flu virus?
  • What protective mechanisms are offered by well-balanced humidification?

The study results show that dry indoor air increases the impact of the flu virus. These results prove that keeping relative humidity levels between 40 and 60 percent minimises the risk of viral infection and makes it harder for the virus to spread. This is the first study that elucidates the physiological mechanisms behind the positive results that are achieved by ensuring well-balanced room air humidification.

Dr Iwasaki answers the most important questions in this video about the recent study.

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Professor Dr. Akiko Iwasaki
Head of Yale study