Causes of Common Cold
Causes of the common cold are almost exclusively viral, with over 200 different viruses known to trigger the condition. The most common culprit is the rhinovirus, responsible for up to 50% of all colds. Other viruses such as coronavirus (non-COVID), respiratory syncytial virus (RSV), adenovirus, and parainfluenza virus also contribute to seasonal colds. Once the virus enters the body, typically through the nose or mouth, it begins to infect the cells of the upper respiratory tract.
The common cold spreads through respiratory droplets released when an infected person sneezes, coughs, or talks. It can also be passed along by touching contaminated surfaces—like doorknobs, keyboards, or mobile phones—and then touching the nose, eyes, or mouth. Viruses can survive on hard surfaces for several hours, making indirect transmission common.
People are more susceptible to catching a cold when their immune systems are weakened. This can be due to factors such as:
- Lack of sleep
- Poor nutrition
- Stress
- Smoking
- Chronic illness
The common cold is also more likely to spread in enclosed environments such as schools, public transport, and offices—particularly in colder months when people spend more time indoors. Dry air from central heating can dry out the nasal passages, making them more vulnerable to infection.
Causes of Common Cold
Interestingly, cold weather itself does not directly cause colds, but exposure to cold air may suppress immune function slightly and lead to behaviours (such as indoor crowding) that increase transmission risk.
Children are especially prone to colds, often experiencing several infections per year. This is due to their developing immune systems and frequent exposure to other children in school or daycare settings.
To summarise, the causes of the common cold involve a range of viruses that spread easily through human contact and environmental surfaces. While these viruses are unavoidable, proper hygiene and immune support can reduce the frequency and severity of infections.
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