How Influenza is Spread

Influenza viruses are mainly spread when infected people cough or sneeze, releasing small virus-containing droplets into the air which can be breathed in and infect the respiratory tract of the people around them. Contaminated respiratory secretions on hands and other surfaces can also transmit the infection by hand to mouth or eye infection.

It has been found that influenza viruses can survive for:

  • Up to an hour in the air in enclosed environments1
  • More than eight hours on hard surfaces such as stainless steel and plastic2
  • Up to five minutes on hands after transfer from other surfaces2

One very important factor in the spread of influenza is that early in infection, even before symptoms become evident, an infected person can be shedding influenza viruses and infecting the people around them.

Good cough and sneeze etiquette and hand washing can contribute to limiting the spread of influenza and other respiratory virus infections.

It is generally believed that young children are the greatest spreaders of influenza because they generate more viruses in their respiratory tract and are less likely to practice good hygiene.


         1. Knight V. Viruses as agents of airborne contagion [chapter V]. Annals of the New York Academic Sciences 1980;353:147-156

         2. Bean B, Moore BM, Sterner B et al. Survival of influenza virus on environmental surfaces. J Infect Dis July 1982;146(1):47-51  


Page publicaton:  January 2014

Last updated:  June 2017