Causes and Risk Factors of Colds

Colds are caused by viruses that spread from person to person through respiratory droplets (for example, through coughing or sneezing). While a number of viruses can cause the common cold, the flu is specifically caused by the influenza virus.

how the common cold spreads
Verywell / Ellen Lindner

Common Causes

Many viruses can prompt cold symptoms—like runny nose, headache, and cough—but rhinoviruses are the most common.

Other viruses that cause colds include:

Risk Factors

Certain things can increase your chances of getting colds, including environmental factors that make it easier for the viruses to spread and medical conditions that affect the body’s ability to protect itself.

Environmental Risk Factors

Both cold and flu viruses are spread through things like cough, sneezing, or wiping your nose and touching objects or other people. As a result, certain situations or environments can make it easier for viruses to spread from person to person. These include:

  • Crowded spaces: When a person infected coughs or sneezes, viruses can travel up to 6 feet away. Frequenting places where a lot of people come in close contact with one another—such as train stations, schools, or nursing facilities—increases your chances of coming in contact with cold viruses, especially during the wintertime.
  • Shared surfaces: Cold viruses can live on surfaces for hours, making shared objects like doorknobs and handrails prime real estate for viruses looking to find their next host.
  • Sanitary conditions: When you’re infected with cold viruses and wipe or blow your nose, the viruses get onto your hand or tissue and, from there, can transfer to other people or objects. Spending a lot of time in places where you can’t wash your hands or where surfaces aren’t frequently disinfected can increase your chances of becoming infected yourself.

Health Risk Factors

Not everyone exposed to cold viruses will get sick. Sometimes the body is able to fight off an infection early to prevent any symptoms from appearing.

Some people are more likely to get seriously sick with either a cold or the flu (or other respiratory illnesses) because of their age, medical history or vaccination status. 

  • Age: Young children and older adults are more susceptible to getting sick with colds and flu and are particularly vulnerable to experiencing serious complications.
  • Medical history: Some medical conditions can make it harder for your body to fight off diseases or be exacerbated by colds or the flu. Pregnant women and those with asthma, heart disease, diabetes, HIV infection, cancer, or certain neurologic conditions are more likely than others to get severely sick with diseases like the flu.

Frequently Asked Questions

  • What is the cause of a common cold?

    The common cold is an infection of the upper respiratory tract caused by any one of more than 200 different viral strains. The viruses most commonly associated with the cold are (by their general order of frequency):

    • Rhinoviruses
    • Coronaviruses
    • Influenza viruses
    • Adenoviruses
    • Human respiratory syncytial viruses
    • Respiratory enteroviruses
    • Parainfluenza viruses
    • Metapneumoviruses
  • How is the common cold transmitted?

    The common cold is transmitted via airborne droplets, contact with nasal secretions, and contact with contaminated objects. Routine hand washing significantly reduces the risk of infection, particularly during cold and flu season. Wearing a face mask may be appropriate when around people who may be infected.

  • What increases the risk of getting a cold?

    Having a chronic illness or weakened immune system increases your risk of getting a cold, as does being under the age of 6 (since the immune system is still not fully mature). Smoking also disrupts the immune response, increasing the risk of colds as well as other respiratory infections.

  • When are you most likely to get a cold?

    You are most likely to get a cold in the fall and winter when temperatures are cooler. With that said, you can get a cold any time of the year. This is because certain cold viruses, such as respiratory syncytial viruses and some enteroviruses, persist and even thrive in warm weather.

  • Who is at risk of complications from a cold?

    People with severe chronic respiratory diseases, such as COPD, are at risk of secondary infections like acute bronchitis, sinusitis, middle ear infections, and pneumonia following a cold. People with asthma may be at risk of asthma attacks, while younger children may be vulnerable to croup.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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