Variability in Donor Lung Culture and Relative Humidity Impact the Stability of 2009 Pandemic H1N1 Influenza Virus on Nonporous Surfaces.

Respiratory viruses can be transmitted by multiple modes, including contaminated surfaces, commonly referred to as fomites. Efficient fomite transmission requires that a virus remain infectious on a given surface material over a wide range of environmental conditions, including different relative humidities. Prior work examining the stability of influenza viruses on surfaces has relied upon virus grown in media or eggs, which does not mimic the composition of virus-containing droplets expelled from the human respiratory tract.

Secondary infection with decreases influenza virus replication and is linked to severe disease.

Secondary bacterial infection is a common complication in severe influenza virus infections. During the H1N1 pandemic of 2009, increased mortality was observed among healthy young adults due to secondary bacterial pneumonia, one of the most frequent bacterial species being (Spn). Previous studies in mice and ferrets have suggested a synergistic relationship between Spn and influenza viruses.

Pre-existing heterosubtypic immunity provides a barrier to airborne transmission of influenza viruses.

Human-to-human transmission of influenza viruses is a serious public health threat, yet the precise role of immunity from previous infections on the susceptibility to airborne infection is still unknown. Using the ferret model, we examined the roles of exposure duration and heterosubtypic immunity on influenza transmission. We demonstrate that a 48 hour exposure is sufficient for efficient transmission of H1N1 and H3N2 viruses.