New study: Dry air is flu’s best friend
A recently published scientific study by Yale University has shown that breathing air with a low humidity reduces our immune system’s capability to fight off flu infections. The research results showed that using humidifiers in the winter to increase the moisture content of air in occupied buildings, such as offices, schools and hospitals, is a potential strategy to reduce the seasonal impact of flu on society.

It is estimated that in the UK influenza causes six million working days to be lost every year, accounts for 400,000 GP consultations, 600 deaths directly and an estimated 10,000 further deaths from flu-related causes. Even though many scientific studies, such as the recent one from Yale, have shown the importance of humidity in relation to combatting flu, no legal requirement exists in the UK for public or commercial buildings to maintain a minimum indoor humidity level for health.

The Yale study, carried out in the laboratory of Dr Akiko Iwasaki, used mice that respond to flu in a similar way to humans. The mice were infected with flu and kept in either low humidity or mid-level humidity conditions. Their physical reactions to the flu virus were then examined, including weight loss, temperature changes, their ability to clear the virus from their respiratory system and heal resultant inflammation, and ultimately their mortality rate.

Study: Low ambient humidity impairs barrier function and innate resistance against influenza infection. PNAS May 28, 2019 116 (22) 10905-10910; first published May 13, 2019. Eriko Kudo, Eric Song, Laura Yockey, Tasfia Rakib, Patrick Wong, Robert Homer, Akiko Iwasaki