A cold is caused by infection with one of many respiratory viruses (most often rhinoviruses) that invade the lining of your nose and throat and trigger inflammation.

What actually causes a cold?

  • The common cold is a viral infection of the upper respiratory tract (nose, sinuses, throat).
  • More than 200 different respiratory viruses can cause it, with rhinoviruses being the most frequent cause worldwide.
  • Other viruses that commonly cause colds include common human coronaviruses, parainfluenza viruses, adenoviruses, enteroviruses, RSV, and human metapneumovirus.

How the virus gets into your body

  • Cold viruses enter through your mouth, nose, or eyes, usually when you breathe in droplets from a sick person’s cough, sneeze, or speech.
  • You can also catch a cold by touching contaminated surfaces (doorknobs, phones, toys) and then touching your nose, eyes, or mouth.
  • Close contact like handshakes or being in crowds (schools, planes, public transport) makes spread more likely.

What does not directly cause a cold?

  • Being out in cold weather or going outside with wet hair does not by itself create a cold; you still need a virus to get infected.
  • However, colds are more common in fall and winter, partly because people spend more time indoors in close contact and indoor air is drier.

Why some people catch colds more easily

  • Children, especially those in daycare or school, get more colds because they are exposed to many viruses and their immune systems are still developing.
  • You are more likely to catch a cold if you smoke or are exposed to secondhand smoke, or if you have a weakened immune system from chronic illness.
  • Not getting enough sleep and chronic stress have been linked with a higher chance of coming down with a cold after exposure.

Quick FAQ style scoop

  • Why do colds feel “worse” in winter?
    Drier air can dry nasal passages and may help viruses survive and spread, plus people crowd indoors more.
  • Why do colds spread so fast in schools and offices?
    Shared surfaces, close seating, and frequent face-to-face interaction increase transmission.
  • Can a cold turn into something more serious?
    Yes; in some cases it can lead to sinus infections, bronchitis, or pneumonia, especially in people with asthma or weak immunity.

Information gathered from public forums or data available on the internet and portrayed here.