section_path: Causes/Transmission
section_name: Transmission
paragraph_text: Transmission
  
  The common cold virus is typically transmitted via airborne droplets, direct contact with infected nasal secretions, or fomites (contaminated objects). Which of these routes is of primary importance has not been determined. As with all respiratory pathogens once presumed to transmit via respiratory droplets, it is highly likely to be carried by the aerosols generated during routine breathing, talking, and singing. The viruses may survive for prolonged periods in the environment (over 18 hours for rhinoviruses) and can be picked up by people's hands and subsequently carried to their eyes or noses where infection occurs. Transmission from animals is considered highly unlikely; an outbreak documented at a British scientific base on Adelaide Island after seventeen weeks of isolation was thought to have been caused by transmission from a contaminated object or an asymptomatic human carrier, rather than from the husky dogs which were also present at the base.
  
  Transmission is common in daycare and schools due to the proximity of many children with little immunity and poor hygiene. These infections are then brought home to other members of the family. There is no evidence that recirculated air during commercial flight is a method of transmission. People sitting close to each other appear to be at greater risk of infection.
  
  Rhinovirus-caused colds are most infectious during the first three days of symptoms; they are much less infectious afterwards.