The common cold is caused by a large number of viruses. Over 200 viruses have been identified as causing colds, many of which are classified as rhinoviruses. These viruses are constantly present in the environment, and infection can occur from physical contact with infected people or surfaces, breathing in small-particle aerosols containing virus in the air, or being directly hit by large-particle aerosols from a person coughing or sneezing.[1][2] Infections are most common in the winter and spring and during rainy seasons in tropical areas.[1]
What causes the common cold?
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•Last Updated: May 16, 2025
The common cold is caused by over 200 viruses, primarily rhinoviruses, which are present in the environment and can be transmitted through contact with infected individuals or surfaces, as well as through airborne particles from coughing or sneezing. Infections are most prevalent during the winter and spring and rainy seasons in tropical regions.