than three feet -RRB- through the air and can be deposited on the mouth or in the nose of people or on surfaces . Those who develop influenza often shed large amounts of virus in their respiratory secretions for several days after they become ill . Experience with other viruses suggests that individuals with influenza can contaminate their hands when coughing , sneezing or blowing their noses . The virus can survive on the hands for at least one hour . If a person whose hands are heavily contaminated touches a surface such as a doorknob , table or computer keyboard , they can deposit the virus onto that surface , where it can survive for minutes to several hours . One study conducted with a regular seasonal strain of influenza virus found that the virus could survive on facial tissues for several minutes and for two to eight hours on stainless steel or plastic surfaces . If another person touches a contaminated surface with his hands when the virus is still alive and then touches his own mouth or nose , he may become infected . Infection might also occur when a person with influenza shakes hands with another
Editor 's note : Dr. John Boyce , chief of the Infectious Diseases Section at the Hospital of Saint Raphael in New Haven , Connecticut , was lead author of the Centers for Disease Control 's national hand hygiene guidelines for health-care workers and heads the Hand Hygiene Resource Center . Dr. John Boyce says hands contaminated with virus are often a pathway for people to develop flu . -LRB- CNN -RRB- -- The rapid spread of the 2009 H1N1 influenza virus -LRB- also known as swine flu -RRB- from Mexico to at least 19 other countries in less than 10 days is a cause of major concern . It emphasizes the need for the public to become familiar with how influenza is spread and which preventive measures they can use to reduce their chances of becoming infected . Although little information is available at this time , it appears that this influenza virus spreads from one person to another in the same way as other influenza viruses -- by `` droplet spread . '' Respiratory droplets are generated when an infected person coughs or sneezes and expels droplets of fluid . Those droplets travel short distances -LRB- usually less