The Causes of the Common Cold

A cold is a viral infection of the upper respiratory tract that causes a sore throat and a runny nose, and several other issues. Many different viruses cause colds, but the most common is rhinovirus. This agent thrives in the distinctive temperature of the human nose. Several different methods of transmission and risk factors increase the chance of a person contracting the common cold.

PeopleImages / Getty Images

Different methods can transmit the common cold:

• Airborne droplets, or aerosols, can carry the virus from person to person when someone with the virus talks, sneezes, or coughs.
• People can contract a cold by touching their eyes, nose, or mouth after having physical contact with a sick person.
• Handling of fomites, objects that can carry the virus such as utensils, towels, or toys, can also lead to contraction of a cold.

Rhinovirus can survive for over 18 hours in these environments and remain infectious.

wilpunt / Getty Images

Children younger than six years old are most likely to contract the common cold. Not only do they have less-developed immune systems, but they are also likely to spend time around other children in day care centers or schools. Children are less conscious of the spread of viruses, so they will cough and sneeze without covering their mouths, and touch a large variety of objects and toys, contaminating them in the process.

asiseeit / Getty Images

Many conditions and variables can cause a weakened immune system. Some people are born with primary immune deficiency diseases. Others may have weak immune systems as the result of burns, diabetes, or chemotherapy. Bodies with immune systems too weak to fight off the virus are easy targets for infection.

BartekSzewczyk / Getty Images

The cold received its name as the result of the theory that exposure to cold or wet weather is a cause. Whether this is true has not been conclusively determined, but experts know people are more likely to catch a cold during cold and wet periods. There are several possible reasons for this. Cold temperatures can cause changes in the respiratory system, or low humidity could allow small viral droplets to stay in the air longer and travel further. Also, people tend to stay indoors more often in cold weather, which facilitates the transmission of disease.

yanikap / Getty Images

Smoking leaves smokers to experience more exaggerated responses to viral infections. Originally, some researchers believed this to be the result of a decreased antiviral response. However, recently, several Yale researchers found cigarette smoke caused the immune systems of mice to overreact, scarring the airways and causing more respiratory issues. Whether one or both of these is correct, most experts accept that smoking increases the risk of catching a cold.

Terroa / Getty Images

Being in close proximity to others is another leading risk factor for the common cold. Public transit, in particular, is ideal for viral travel. Airplanes, trains, and subways are essentially cans infected air from hundreds of individuals.

undefined undefined / Getty Images

Though colds are usually not severe, they can cause complications such as asthma attacks in people already susceptible to the events. If the cold does not resolve promptly, children and adults may experience inflammation and infection of the sinuses. Children specifically may contract strep throat or pneumonia if the cold is severe enough.

Rostislav_Sedlacek / Getty Images

The cold and the flu are both viral respiratory infections and as a result, can be difficult to tell apart. Treatment differs, so knowing which infection you have is important. First, colds are gradual. It can take several days for cold symptoms to appear, while the flu is sudden. The flu often comes along with a fever while colds do not. Finally, the flu commonly causes physical aches and nausea, while those symptoms are rare for colds.

laflor / Getty Images

The cold has no cure, so the only way to really prevent it is to practice safe habits. Physical measures such as hand washing and protective face masks can help prevent the spread of viruses. Many of the other methods of preventing colds are inconclusive at best. There is no proof that zinc supplements or antivirals affect the cold virus. Vitamin C supplements may reduce the duration of a cold, but do not appear to affect the severity.

PeopleImages / Getty Images