Myth: Breathing the same air as a sick person is the easiest way to catch a cold.

Reality: Cold viruses can travel through the air — especially when a sick person coughs or sneezes — but it’s not a very efficient way for them to find their next victim. They’d much rather hitch a ride on a person’s hand. One of the best ways to catch a cold is to grab something that’s coated with the virus, perhaps a phone, toy or friend’s hand. 

Source: https://www.avera.org/services/wellness-preventive/health-wellness-information/the-truth-about-colds–flu/