How the influenza virus travels in droplets and enters mucous membranes
In everyday life, influenza virus particles travel in droplets larger than 5 microns in diameter, which are released or "shed" from infected persons when they sneeze, cough, or talk. These are large droplets.
This is an important detail, because large droplets do not travel very far. It is thought that they spread no farther than 1 metre, which is the basis of the "less than 1 metre" principle: the distance that people should stay apart to limit the risk of infection. Other types of infections, like tuberculosis and chicken pox, can travel in "aerosols," which means they can be suspended in smaller particles with the ability to travel farther.
To infect you, influenza must enter your body through mucous membranes: your eyes, your nose, or your mouth. The relatively large droplets containing influenza virus can directly infect you if you are less than 1 metre from an infected person. This may happen if an infected person sheds virus while coughing, sneezing, or talking and the virus particles enter your eyes, nose, or mouth. Droplets may also deposit themselves on an object; if you touch this object, you then bring the virus to your own mucous membranes by touching them.
Guard your mucous membranes: wash your hands
Handwashing is the single most powerful personal measure that can reduce your chance of contracting influenza during a pandemic.
This is what happens: People with influenza cough, clear their throats, talk, or sneeze on their hands. They open doors and push elevator buttons. They may not realize they're sick, because a person with influenza can be contagious and shedding virus particles one day before any symptoms appear. Influenza virus particles can survive on inanimate objects: up to 48 hours on hard surfaces, up to 12 hours on cloth or tissues. You open a door or push an elevator button in the wake of someone with influenza, you might rub a bit of dust from your eye or scratch your nose. Now, you may have infected yourself with influenza.
Page 1 of 4 – On page 2, find etiquette guidelines to follow around someone who's coughing or sneezing around you.
Excerpted from The Flu Pandemic and You: A Canadian Guide by Vincent Lam, M.D. and Colin Lee, M.D. Copyright 2006 Vincent Lam and Colin Lee. Reprinted by permission of Doubleday Canada.
