Mucus and other airway secretions that are expelled when a person with the flu coughs or exhales appear to protect the virus when it becomes airborne, regardless of humidity levels, a creative experiment conducted by the University of Pittsburgh and Virginia Tech discovered.
The results, published in today’s issue of the Journal of Infectious Diseases, refute long-standing studies that indicated the influenza virus degrades and is inactivated sooner as the humidity increases.
“Our findings highlight the importance of mimicking real-world conditions when determining the infectivity of emerging viruses,” said Seema S. Lakdawala, Ph.D., assistant professor in the Pitt School of Medicine’s Department of Microbiology & Molecular Genetics. “This has critical implications when public health organizations devise ways to stem the spread of infections, particularly during pandemics.”
Influenza viruses emerge every winter in temperate regions when people are in closer contact inside, better enabling person-to-person spread. But it is also much less humid inside buildings that are heated in winter, and previous experiments using aerosolized flu virus alone – not in combination with airway secretions – showed that moderate to high humidity inactivated the virus. So it was assumed that dry winter air had a protective effect that also allowed the flu virus to thrive.
Read more at Schools of Health Sciences (University of Pittsburgh)