The common cold is a social disease. You can only catch a cold by being chummy with a person carrying a cold virus. The most common virus is the rhinovirus and, as its name suggests, it causes the runny nose, sore throat and mild cough kind of cold. Rhinovirus accounts for 50 percent of all colds and comes in 100 different subtypes, which is why efforts to develop a vaccine have failed so far. Colds (also called upper respiratory infections) that include lots of coughing may be caused by Respiratory Syncytial Virus (RSV) or the influenza virus.
A cold causing virus can find you through a casual handshake with an infected buddy, or even a door knob recently handled by a person after a sneeze. Droplets in the air are less effective at spreading a cold. Passengers in airplanes where the air is re-circulated are no more likely to catch a cold than passengers aboard airplanes where 100 percent of the air is fresh.
Acute stress nearly doubles the chance a cold virus will cause symptoms, which explains the many sniffles in an exam room.
What about getting chilled? Inhaled cold air has been shown to inhibit the ability to clear mucous and the aggressiveness of white blood cells which are supposed to gobble up viruses before they are a problem. Rhinovirus also grows better at slightly cooler room temperatures, but clinical studies have not yet shown any relationship between “catching a chill” and catching a cold. It is more likely that sharing of confined spaces during winter months increases exposure time to people carrying, and sharing, cold viruses. One paradox is that continuous participation in diverse social networks maintains the currency of antibodies and makes you more resistant to becoming ill.
Fortunately colds are self-limited illnesses. They last fewer than 14 days, usually spanning five to seven days. When they last longer, there is usually a complication, like asthma or other lung disease. So, do no harm. Antibiotics can cause rashes and don’t kill viruses so avoid them. Drink fluids, rest, use acetaminophen for aches, pseudoephedrine for stuffy nose, dextromethorphan for cough. And please, don’t shake hands with people you like.