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The common cold is a viral infectious disease that affects the upper respiratory system. It is the most common infectious disease among humans.

Most colds result from coronaviruses or rhinoviruses. The coronavirus that causes a cold is different from SARS-CoV-2, which causes COVID-19. COVID-19 and a cold are different diseases.

Many types of virus can cause a cold, and the human body can never build up resistance to them all. This is why colds are so common and often return.

According to the Centers for Disease Control and Prevention (CDC), adults on average get 2–3 colds per year, and children may have more. They usually last around 7–10 days.

Colds spread through droplets in the air and on surfaces.

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When a person has a cold virus, their immune system tries to fight it off. This causes the symptoms that we recognize as a cold.

Symptoms can vary, but common ones include:

Rarer symptoms include:

People with a weakened immune system may develop more severe symptoms or a secondary infection, such as pneumonia. If a person develops more serious symptoms, they should seek medical help.

The symptoms of a cold develop in stages. Here, get more detail about the stages of a cold.

Is it coronavirus?

Anyone who has the following symptoms should stay away from other people and seek medical advice:

  • a high temperature
  • a new, continuous cough
  • a loss or change to the senses of smell or taste

These are common symptoms of COVID-19. Click here to learn more.

If a person experiences the following, they should seek emergency medical care at once:

  • difficulty breathing
  • pain or tightening in the chest
  • confusion
  • an inability to stay awake
  • bluish lips or face

They or another person should call 911 or the local emergency department to ask for instructions.

Over 200 different viruses can cause cold symptoms, and rhinoviruses are responsible for most of them.

When a virus enters the body, the immune system tries to fight it. In a person with a strong immune system, symptoms may not develop.

However, if the immune system cannot fight off the virus, symptoms of infection will appear.

Colds can affect anyone at any time of year, but some factors can increase the risk:

  • being a young child or an older adult
  • having a weak immune system
  • seasonal factors, as colds are more common in winter
  • having close contact with someone who has a cold

A cold is not usually serious, and colds mostly disappear after 7–10 days. Sometimes, however, complications can occur. These are most likely to affect those with a weakened immune system.

They include:

A cold can worsen the symptoms of asthma and chronic obstructive pulmonary disease (COPD) — which includes emphysema and chronic bronchitis.

As so many viruses can cause a cold, it is difficult to develop a vaccine.

However, people can take precautions to help prevent catching a cold.

These include:

  • Avoiding close contact with anyone who has a cold.
  • Following a healthful and varied diet with plenty of fresh fruits and vegetables.
  • Always sneezing or coughing into a tissue, then discarding the tissue carefully and washing your hands at once.
  • If there is no tissue available, coughing or sneezing into the upper shirt sleeve, covering the nose and mouth completely.
  • Washing hands regularly with soapy water for at least 20 seconds.
  • Keeping surfaces at work and in the home.
  • Avoiding touching the face, especially the eyes, nose, and mouth.

Learn more here about how to stall a cold that is just starting.

There is no cure for a cold, but treatment can help manage symptoms.

Here are some tips:

  • Drink plenty of fluids to prevent dehydration.
  • Get plenty of rest.
  • Use over-the-counter medications to manage pain and discomfort.
  • Inhale steam, which may help relieve nasal congestion.
  • Gargle saltwater for a sore throat.

People use various natural remedies for colds. Some, such as drinking warm lemon and honey, may provide relief. However, not all of them have scientific evidence that confirms that they are useful.

Over-the-counter remedies for a cold are available at drugstores, in pharmacies, and online.

If people develop complications, a doctor may prescribe antiviral medication or antibiotics, depending on the type of complication.

Here, find out more about how to treat a cold.

Most people do not need to consult a doctor for a cold. However, if symptoms worsen or become more serious, this may be a sign of a complication.

A person should seek medical advice if:

  • a cold lasts longer than 10 days
  • a child is under 3 months of age and has a fever or lethargy
  • symptoms are severe or unusual
  • there is a high fever

Anyone who develops breathing difficulties should contact the emergency room at once.

The symptoms of a cold and the flu can be similar.

However, flu symptoms tend to:

  • appear more suddenly
  • be more intense
  • last longer
  • include a fever and body aches

Flu vaccinations are available from pharmacies or the doctor’s office. Most people should consider having an annual vaccine to protect themselves.

Here, learn more about the differences between a cold and the flu.

Most people experience a cold from time to time. A cold is not usually serious, but it can lead to complications in older people and those with a weakened immune system.

There is no cure for a cold, but treatment can provide temporary relief from symptoms. Hand-washing and other hygiene practices can help prevent a cold.