Survival of influenza virus on human fingers.

Indirect transmission of the influenza virus via finger contamination with respiratory mucus droplets has been hypothesized to contribute to transmission in the community. Under laboratory conditions, influenza-infected respiratory droplets were reconstituted as close as possible to natural conditions. We investigated experimentally the survival of influenza A (H3N2) and A (H1N1)pdm09 viruses on human fingers. Infectious virus was easily recoverable on all fingers 1 min after fingertip contamination but then decreased very rapidly. After 30 min, infectious virus was detectable in only a small minority of subjects. Infectious viruses were detected for a longer period of time when droplets of larger size containing a higher number of particles were tested or when the viral concentration increased. A rapid decrease in infectiousness was observed when droplet integrity was disrupted. Our findings could help to set up the promotion of hand hygiene to prevent influenza hand contamination.